diff options
| -rw-r--r-- | arch/s390/include/asm/ccwgroup.h | 1 | ||||
| -rw-r--r-- | arch/s390/pci/pci_sysfs.c | 18 | ||||
| -rw-r--r-- | dir.c | 1248 | ||||
| -rw-r--r-- | drivers/base/core.c | 50 | ||||
| -rw-r--r-- | drivers/base/dma-buf.c | 18 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_prime.c | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 2 | ||||
| -rw-r--r-- | drivers/media/v4l2-core/videobuf2-dma-contig.c | 2 | ||||
| -rw-r--r-- | drivers/pci/pci-sysfs.c | 17 | ||||
| -rw-r--r-- | drivers/s390/block/dcssblk.c | 14 | ||||
| -rw-r--r-- | drivers/s390/cio/ccwgroup.c | 26 | ||||
| -rw-r--r-- | drivers/scsi/scsi_sysfs.c | 15 | ||||
| -rw-r--r-- | fs/Kconfig | 1 | ||||
| -rw-r--r-- | fs/Makefile | 3 | ||||
| -rw-r--r-- | fs/kernfs/Kconfig | 7 | ||||
| -rw-r--r-- | fs/kernfs/dir.c | 750 | ||||
| -rw-r--r-- | fs/kernfs/file.c | 55 | ||||
| -rw-r--r-- | fs/kernfs/kernfs-internal.h | 14 | ||||
| -rw-r--r-- | fs/kernfs/mount.c | 37 | ||||
| -rw-r--r-- | fs/kernfs/symlink.c | 6 | ||||
| -rw-r--r-- | fs/sysfs/Kconfig | 1 | ||||
| -rw-r--r-- | fs/sysfs/dir.c | 44 | ||||
| -rw-r--r-- | fs/sysfs/file.c | 115 | ||||
| -rw-r--r-- | fs/sysfs/mount.c | 2 | ||||
| -rw-r--r-- | include/linux/device.h | 13 | ||||
| -rw-r--r-- | include/linux/kernfs.h | 108 | ||||
| -rw-r--r-- | include/linux/sysfs.h | 23 | ||||
| -rw-r--r-- | lib/kobject.c | 2 |
28 files changed, 2091 insertions, 503 deletions
diff --git a/arch/s390/include/asm/ccwgroup.h b/arch/s390/include/asm/ccwgroup.h index 23723ce..6e670f8 100644 --- a/arch/s390/include/asm/ccwgroup.h +++ b/arch/s390/include/asm/ccwgroup.h @@ -23,6 +23,7 @@ struct ccwgroup_device { unsigned int count; struct device dev; struct ccw_device *cdev[0]; + struct work_struct ungroup_work; }; /** diff --git a/arch/s390/pci/pci_sysfs.c b/arch/s390/pci/pci_sysfs.c index cf8a12f..ab4a913 100644 --- a/arch/s390/pci/pci_sysfs.c +++ b/arch/s390/pci/pci_sysfs.c @@ -48,29 +48,27 @@ static ssize_t show_pfgid(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR(pfgid, S_IRUGO, show_pfgid, NULL); -static void recover_callback(struct device *dev) +static ssize_t store_recover(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) { struct pci_dev *pdev = to_pci_dev(dev); struct zpci_dev *zdev = get_zdev(pdev); int ret; + if (!device_remove_file_self(dev, attr)) + return count; + pci_stop_and_remove_bus_device(pdev); ret = zpci_disable_device(zdev); if (ret) - return; + return ret; ret = zpci_enable_device(zdev); if (ret) - return; + return ret; pci_rescan_bus(zdev->bus); -} - -static ssize_t store_recover(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count) -{ - int rc = device_schedule_callback(dev, recover_callback); - return rc ? rc : count; + return count; } static DEVICE_ATTR(recover, S_IWUSR, NULL, store_recover); @@ -0,0 +1,1248 @@ +/* + * fs/kernfs/dir.c - kernfs directory implementation + * + * Copyright (c) 2001-3 Patrick Mochel + * Copyright (c) 2007 SUSE Linux Products GmbH + * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org> + * + * This file is released under the GPLv2. + */ + +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/idr.h> +#include <linux/slab.h> +#include <linux/security.h> +#include <linux/hash.h> + +#include "kernfs-internal.h" + +DEFINE_MUTEX(kernfs_mutex); + +#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) + +static bool kernfs_active(struct kernfs_node *kn) +{ + lockdep_assert_held(&kernfs_mutex); + return atomic_read(&kn->active) >= 0; +} + +static bool kernfs_lockdep(struct kernfs_node *kn) +{ +#ifdef CONFIG_DEBUG_LOCK_ALLOC + return kn->flags & KERNFS_LOCKDEP; +#else + return false; +#endif +} + +/** + * kernfs_name_hash + * @name: Null terminated string to hash + * @ns: Namespace tag to hash + * + * Returns 31 bit hash of ns + name (so it fits in an off_t ) + */ +static unsigned int kernfs_name_hash(const char *name, const void *ns) +{ + unsigned long hash = init_name_hash(); + unsigned int len = strlen(name); + while (len--) + hash = partial_name_hash(*name++, hash); + hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31)); + hash &= 0x7fffffffU; + /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ + if (hash < 1) + hash += 2; + if (hash >= INT_MAX) + hash = INT_MAX - 1; + return hash; +} + +static int kernfs_name_compare(unsigned int hash, const char *name, + const void *ns, const struct kernfs_node *kn) +{ + if (hash != kn->hash) + return hash - kn->hash; + if (ns != kn->ns) + return ns - kn->ns; + return strcmp(name, kn->name); +} + +static int kernfs_sd_compare(const struct kernfs_node *left, + const struct kernfs_node *right) +{ + return kernfs_name_compare(left->hash, left->name, left->ns, right); +} + +/** + * kernfs_link_sibling - link kernfs_node into sibling rbtree + * @kn: kernfs_node of interest + * + * Link @kn into its sibling rbtree which starts from + * @kn->parent->dir.children. + * + * Locking: + * mutex_lock(kernfs_mutex) + * + * RETURNS: + * 0 on susccess -EEXIST on failure. + */ +static int kernfs_link_sibling(struct kernfs_node *kn) +{ + struct rb_node **node = &kn->parent->dir.children.rb_node; + struct rb_node *parent = NULL; + + if (kernfs_type(kn) == KERNFS_DIR) + kn->parent->dir.subdirs++; + + while (*node) { + struct kernfs_node *pos; + int result; + + pos = rb_to_kn(*node); + parent = *node; + result = kernfs_sd_compare(kn, pos); + if (result < 0) + node = &pos->rb.rb_left; + else if (result > 0) + node = &pos->rb.rb_right; + else + return -EEXIST; + } + /* add new node and rebalance the tree */ + rb_link_node(&kn->rb, parent, node); + rb_insert_color(&kn->rb, &kn->parent->dir.children); + return 0; +} + +/** + * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree + * @kn: kernfs_node of interest + * + * Try to unlink @kn from its sibling rbtree which starts from + * kn->parent->dir.children. Returns %true if @kn was actually + * removed, %false if @kn wasn't on the rbtree. + * + * Locking: + * mutex_lock(kernfs_mutex) + */ +static bool kernfs_unlink_sibling(struct kernfs_node *kn) +{ + if (RB_EMPTY_NODE(&kn->rb)) + return false; + + if (kernfs_type(kn) == KERNFS_DIR) + kn->parent->dir.subdirs--; + + rb_erase(&kn->rb, &kn->parent->dir.children); + RB_CLEAR_NODE(&kn->rb); + return true; +} + +/** + * kernfs_get_active - get an active reference to kernfs_node + * @kn: kernfs_node to get an active reference to + * + * Get an active reference of @kn. This function is noop if @kn + * is NULL. + * + * RETURNS: + * Pointer to @kn on success, NULL on failure. + */ +struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) +{ + if (unlikely(!kn)) + return NULL; + + if (!atomic_inc_unless_negative(&kn->active)) + return NULL; + + if (kernfs_lockdep(kn)) + rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); + return kn; +} + +/** + * kernfs_put_active - put an active reference to kernfs_node + * @kn: kernfs_node to put an active reference to + * + * Put an active reference to @kn. This function is noop if @kn + * is NULL. + */ +void kernfs_put_active(struct kernfs_node *kn) +{ + struct kernfs_root *root = kernfs_root(kn); + int v; + + if (unlikely(!kn)) + return; + + if (kernfs_lockdep(kn)) + rwsem_release(&kn->dep_map, 1, _RET_IP_); + v = atomic_dec_return(&kn->active); + if (likely(v != KN_DEACTIVATED_BIAS)) + return; + + wake_up_all(&root->deactivate_waitq); +} + +/** + * kernfs_drain - drain kernfs_node + * @kn: kernfs_node to drain + * + * Drain existing usages and nuke all existing mmaps of @kn. Mutiple + * removers may invoke this function concurrently on @kn and all will + * return after draining is complete. + */ +static void kernfs_drain(struct kernfs_node *kn) + __releases(&kernfs_mutex) __acquires(&kernfs_mutex) +{ + struct kernfs_root *root = kernfs_root(kn); + + lockdep_assert_held(&kernfs_mutex); + WARN_ON_ONCE(kernfs_active(kn)); + + mutex_unlock(&kernfs_mutex); + + if (kernfs_lockdep(kn)) { + rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); + if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) + lock_contended(&kn->dep_map, _RET_IP_); + } + + /* but everyone should wait for draining */ + wait_event(root->deactivate_waitq, + atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); + + if (kernfs_lockdep(kn)) { + lock_acquired(&kn->dep_map, _RET_IP_); + rwsem_release(&kn->dep_map, 1, _RET_IP_); + } + + kernfs_unmap_bin_file(kn); + + mutex_lock(&kernfs_mutex); +} + +/** + * kernfs_get - get a reference count on a kernfs_node + * @kn: the target kernfs_node + */ +void kernfs_get(struct kernfs_node *kn) +{ + if (kn) { + WARN_ON(!atomic_read(&kn->count)); + atomic_inc(&kn->count); + } +} +EXPORT_SYMBOL_GPL(kernfs_get); + +/** + * kernfs_put - put a reference count on a kernfs_node + * @kn: the target kernfs_node + * + * Put a reference count of @kn and destroy it if it reached zero. + */ +void kernfs_put(struct kernfs_node *kn) +{ + struct kernfs_node *parent; + struct kernfs_root *root; + + if (!kn || !atomic_dec_and_test(&kn->count)) + return; + root = kernfs_root(kn); + repeat: + /* + * Moving/renaming is always done while holding reference. + * kn->parent won't change beneath us. + */ + parent = kn->parent; + + WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, + "kernfs_put: %s/%s: released with incorrect active_ref %d\n", + parent ? parent->name : "", kn->name, atomic_read(&kn->active)); + + if (kernfs_type(kn) == KERNFS_LINK) + kernfs_put(kn->symlink.target_kn); + if (!(kn->flags & KERNFS_STATIC_NAME)) + kfree(kn->name); + if (kn->iattr) { + if (kn->iattr->ia_secdata) + security_release_secctx(kn->iattr->ia_secdata, + kn->iattr->ia_secdata_len); + simple_xattrs_free(&kn->iattr->xattrs); + } + kfree(kn->iattr); + ida_simple_remove(&root->ino_ida, kn->ino); + kmem_cache_free(kernfs_node_cache, kn); + + kn = parent; + if (kn) { + if (atomic_dec_and_test(&kn->count)) + goto repeat; + } else { + /* just released the root kn, free @root too */ + ida_destroy(&root->ino_ida); + kfree(root); + } +} +EXPORT_SYMBOL_GPL(kernfs_put); + +static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) +{ + struct kernfs_node *kn; + + if (flags & LOOKUP_RCU) + return -ECHILD; + + /* Always perform fresh lookup for negatives */ + if (!dentry->d_inode) + goto out_bad_unlocked; + + kn = dentry->d_fsdata; + mutex_lock(&kernfs_mutex); + + /* The kernfs node has been deactivated */ + if (!kernfs_active(kn)) + goto out_bad; + + /* The kernfs node has been moved? */ + if (dentry->d_parent->d_fsdata != kn->parent) + goto out_bad; + + /* The kernfs node has been renamed */ + if (strcmp(dentry->d_name.name, kn->name) != 0) + goto out_bad; + + /* The kernfs node has been moved to a different namespace */ + if (kn->parent && kernfs_ns_enabled(kn->parent) && + kernfs_info(dentry->d_sb)->ns != kn->ns) + goto out_bad; + + mutex_unlock(&kernfs_mutex); +out_valid: + return 1; +out_bad: + mutex_unlock(&kernfs_mutex); +out_bad_unlocked: + /* + * @dentry doesn't match the underlying kernfs node, drop the + * dentry and force lookup. If we have submounts we must allow the + * vfs caches to lie about the state of the filesystem to prevent + * leaks and other nasty things, so use check_submounts_and_drop() + * instead of d_drop(). + */ + if (check_submounts_and_drop(dentry) != 0) + goto out_valid; + + return 0; +} + +static void kernfs_dop_release(struct dentry *dentry) +{ + kernfs_put(dentry->d_fsdata); +} + +const struct dentry_operations kernfs_dops = { + .d_revalidate = kernfs_dop_revalidate, + .d_release = kernfs_dop_release, +}; + +static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, + const char *name, umode_t mode, + unsigned flags) +{ + char *dup_name = NULL; + struct kernfs_node *kn; + int ret; + + if (!(flags & KERNFS_STATIC_NAME)) { + name = dup_name = kstrdup(name, GFP_KERNEL); + if (!name) + return NULL; + } + + kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); + if (!kn) + goto err_out1; + + ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL); + if (ret < 0) + goto err_out2; + kn->ino = ret; + + atomic_set(&kn->count, 1); + atomic_set(&kn->active, KN_DEACTIVATED_BIAS); + RB_CLEAR_NODE(&kn->rb); + + kn->name = name; + kn->mode = mode; + kn->flags = flags; + + return kn; + + err_out2: + kmem_cache_free(kernfs_node_cache, kn); + err_out1: + kfree(dup_name); + return NULL; +} + +struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, + const char *name, umode_t mode, + unsigned flags) +{ + struct kernfs_node *kn; + + kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags); + if (kn) { + kernfs_get(parent); + kn->parent = parent; + } + return kn; +} + +/** + * kernfs_add_one - add kernfs_node to parent without warning + * @kn: kernfs_node to be added + * + * The caller must already have initialized @kn->parent. This + * function increments nlink of the parent's inode if @kn is a + * directory and link into the children list of the parent. + * + * RETURNS: + * 0 on success, -EEXIST if entry with the given name already + * exists. + */ +int kernfs_add_one(struct kernfs_node *kn) +{ + struct kernfs_node *parent = kn->parent; + struct kernfs_iattrs *ps_iattr; + bool has_ns; + int ret; + + mutex_lock(&kernfs_mutex); + + ret = -EINVAL; + has_ns = kernfs_ns_enabled(parent); + if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", + has_ns ? "required" : "invalid", parent->name, kn->name)) + goto out_unlock; + + if (kernfs_type(parent) != KERNFS_DIR) + goto out_unlock; + + ret = -ENOENT; + if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) + goto out_unlock; + + kn->hash = kernfs_name_hash(kn->name, kn->ns); + + ret = kernfs_link_sibling(kn); + if (ret) + goto out_unlock; + + /* Update timestamps on the parent */ + ps_iattr = parent->iattr; + if (ps_iattr) { + struct iattr *ps_iattrs = &ps_iattr->ia_iattr; + ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; + } + + mutex_unlock(&kernfs_mutex); + + /* + * Activate the new node unless CREATE_DEACTIVATED is requested. + * If not activated here, the kernfs user is responsible for + * activating the node with kernfs_activate(). A node which hasn't + * been activated is not visible to userland and its removal won't + * trigger deactivation. + */ + if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) + kernfs_activate(kn); + return 0; + +out_unlock: + mutex_unlock(&kernfs_mutex); + return ret; +} + +/** + * kernfs_find_ns - find kernfs_node with the given name + * @parent: kernfs_node to search under + * @name: name to look for + * @ns: the namespace tag to use + * + * Look for kernfs_node with name @name under @parent. Returns pointer to + * the found kernfs_node on success, %NULL on failure. + */ +static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, + const unsigned char *name, + const void *ns) +{ + struct rb_node *node = parent->dir.children.rb_node; + bool has_ns = kernfs_ns_enabled(parent); + unsigned int hash; + + lockdep_assert_held(&kernfs_mutex); + + if (has_ns != (bool)ns) { + WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", + has_ns ? "required" : "invalid", parent->name, name); + return NULL; + } + + hash = kernfs_name_hash(name, ns); + while (node) { + struct kernfs_node *kn; + int result; + + kn = rb_to_kn(node); + result = kernfs_name_compare(hash, name, ns, kn); + if (result < 0) + node = node->rb_left; + else if (result > 0) + node = node->rb_right; + else + return kn; + } + return NULL; +} + +/** + * kernfs_find_and_get_ns - find and get kernfs_node with the given name + * @parent: kernfs_node to search under + * @name: name to look for + * @ns: the namespace tag to use + * + * Look for kernfs_node with name @name under @parent and get a reference + * if found. This function may sleep and returns pointer to the found + * kernfs_node on success, %NULL on failure. + */ +struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, + const char *name, const void *ns) +{ + struct kernfs_node *kn; + + mutex_lock(&kernfs_mutex); + kn = kernfs_find_ns(parent, name, ns); + kernfs_get(kn); + mutex_unlock(&kernfs_mutex); + + return kn; +} +EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); + +/** + * kernfs_create_root - create a new kernfs hierarchy + * @scops: optional syscall operations for the hierarchy + * @priv: opaque data associated with the new directory + * + * Returns the root of the new hierarchy on success, ERR_PTR() value on + * failure. + */ +struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, + void *priv) +{ + struct kernfs_root *root; + struct kernfs_node *kn; + + root = kzalloc(sizeof(*root), GFP_KERNEL); + if (!root) + return ERR_PTR(-ENOMEM); + + ida_init(&root->ino_ida); + + kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, + KERNFS_DIR); + if (!kn) { + ida_destroy(&root->ino_ida); + kfree(root); + return ERR_PTR(-ENOMEM); + } + + kernfs_activate(kn); + kn->priv = priv; + kn->dir.root = root; + + root->syscall_ops = scops; + root->kn = kn; + init_waitqueue_head(&root->deactivate_waitq); + + return root; +} + +/** + * kernfs_destroy_root - destroy a kernfs hierarchy + * @root: root of the hierarchy to destroy + * + * Destroy the hierarchy anchored at @root by removing all existing + * directories and destroying @root. + */ +void kernfs_destroy_root(struct kernfs_root *root) +{ + kernfs_remove(root->kn); /* will also free @root */ +} + +/** + * kernfs_create_dir_ns - create a directory + * @parent: parent in which to create a new directory + * @name: name of the new directory + * @mode: mode of the new directory + * @priv: opaque data associated with the new directory + * @ns: optional namespace tag of the directory + * + * Returns the created node on success, ERR_PTR() value on failure. + */ +struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, + const char *name, umode_t mode, + void *priv, const void *ns) +{ + struct kernfs_node *kn; + int rc; + + /* allocate */ + kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR); + if (!kn) + return ERR_PTR(-ENOMEM); + + kn->dir.root = parent->dir.root; + kn->ns = ns; + kn->priv = priv; + + /* link in */ + rc = kernfs_add_one(kn); + if (!rc) + return kn; + + kernfs_put(kn); + return ERR_PTR(rc); +} + +static struct dentry *kernfs_iop_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags) +{ + struct dentry *ret; + struct kernfs_node *parent = dentry->d_parent->d_fsdata; + struct kernfs_node *kn; + struct inode *inode; + const void *ns = NULL; + + mutex_lock(&kernfs_mutex); + + if (kernfs_ns_enabled(parent)) + ns = kernfs_info(dir->i_sb)->ns; + + kn = kernfs_find_ns(parent, dentry->d_name.name, ns); + + /* no such entry */ + if (!kn || !kernfs_active(kn)) { + ret = NULL; + goto out_unlock; + } + kernfs_get(kn); + dentry->d_fsdata = kn; + + /* attach dentry and inode */ + inode = kernfs_get_inode(dir->i_sb, kn); + if (!inode) { + ret = ERR_PTR(-ENOMEM); + goto out_unlock; + } + + /* instantiate and hash dentry */ + ret = d_materialise_unique(dentry, inode); + out_unlock: + mutex_unlock(&kernfs_mutex); + return ret; +} + +static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, + umode_t mode) +{ + struct kernfs_node *parent = dir->i_private; + struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; + int ret; + + if (!scops || !scops->mkdir) + return -EPERM; + + if (!kernfs_get_active(parent)) + return -ENODEV; + + ret = scops->mkdir(parent, dentry->d_name.name, mode); + + kernfs_put_active(parent); + return ret; +} + +static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct kernfs_node *kn = dentry->d_fsdata; + struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; + int ret; + + if (!scops || !scops->rmdir) + return -EPERM; + + if (!kernfs_get_active(kn)) + return -ENODEV; + + ret = scops->rmdir(kn); + + kernfs_put_active(kn); + return ret; +} + +static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + struct kernfs_node *kn = old_dentry->d_fsdata; + struct kernfs_node *new_parent = new_dir->i_private; + struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; + int ret; + + if (!scops || !scops->rename) + return -EPERM; + + if (!kernfs_get_active(kn)) + return -ENODEV; + + if (!kernfs_get_active(new_parent)) { + kernfs_put_active(kn); + return -ENODEV; + } + + ret = scops->rename(kn, new_parent, new_dentry->d_name.name); + + kernfs_put_active(new_parent); + kernfs_put_active(kn); + return ret; +} + +const struct inode_operations kernfs_dir_iops = { + .lookup = kernfs_iop_lookup, + .permission = kernfs_iop_permission, + .setattr = kernfs_iop_setattr, + .getattr = kernfs_iop_getattr, + .setxattr = kernfs_iop_setxattr, + .removexattr = kernfs_iop_removexattr, + .getxattr = kernfs_iop_getxattr, + .listxattr = kernfs_iop_listxattr, + + .mkdir = kernfs_iop_mkdir, + .rmdir = kernfs_iop_rmdir, + .rename = kernfs_iop_rename, +}; + +static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) +{ + struct kernfs_node *last; + + while (true) { + struct rb_node *rbn; + + last = pos; + + if (kernfs_type(pos) != KERNFS_DIR) + break; + + rbn = rb_first(&pos->dir.children); + if (!rbn) + break; + + pos = rb_to_kn(rbn); + } + + return last; +} + +/** + * kernfs_next_descendant_post - find the next descendant for post-order walk + * @pos: the current position (%NULL to initiate traversal) + * @root: kernfs_node whose descendants to walk + * + * Find the next descendant to visit for post-order traversal of @root's + * descendants. @root is included in the iteration and the last node to be + * visited. + */ +static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, + struct kernfs_node *root) +{ + struct rb_node *rbn; + + lockdep_assert_held(&kernfs_mutex); + + /* if first iteration, visit leftmost descendant which may be root */ + if (!pos) + return kernfs_leftmost_descendant(root); + + /* if we visited @root, we're done */ + if (pos == root) + return NULL; + + /* if there's an unvisited sibling, visit its leftmost descendant */ + rbn = rb_next(&pos->rb); + if (rbn) + return kernfs_leftmost_descendant(rb_to_kn(rbn)); + + /* no sibling left, visit parent */ + return pos->parent; +} + +/** + * kernfs_activate - activate a node which started deactivated + * @kn: kernfs_node whose subtree is to be activated + * + * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node + * needs to be explicitly activated. A node which hasn't been activated + * isn't visible to userland and deactivation is skipped during its + * removal. This is useful to construct atomic init sequences where + * creation of multiple nodes should either succeed or fail atomically. + * + * The caller is responsible for ensuring that this function is not called + * after kernfs_remove*() is invoked on @kn. + */ +void kernfs_activate(struct kernfs_node *kn) +{ + struct kernfs_node *pos; + + mutex_lock(&kernfs_mutex); + + pos = NULL; + while ((pos = kernfs_next_descendant_post(pos, kn))) { + if (!pos || (pos->flags & KERNFS_ACTIVATED)) + continue; + + WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb)); + WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS); + + atomic_sub(KN_DEACTIVATED_BIAS, &pos->active); + pos->flags |= KERNFS_ACTIVATED; + } + + mutex_unlock(&kernfs_mutex); +} + +static void __kernfs_remove(struct kernfs_node *kn) +{ + struct kernfs_node *pos; + + lockdep_assert_held(&kernfs_mutex); + + /* + * Short-circuit if @kn has already finished removal. This is for + * kernfs_remove_self() which plays with active ref after removal. + */ + if (!kn || RB_EMPTY_NODE(&kn->rb)) + return; + + pr_debug("kernfs %s: removing\n", kn->name); + + /* prevent any new usage under @kn by deactivating all nodes */ + pos = NULL; + while ((pos = kernfs_next_descendant_post(pos, kn))) + if (kernfs_active(pos)) + atomic_add(KN_DEACTIVATED_BIAS, &pos->active); + + /* deactivate and unlink the subtree node-by-node */ + do { + pos = kernfs_leftmost_descendant(kn); + + /* + * kernfs_drain() drops kernfs_mutex temporarily and @pos's + * base ref could have been put by someone else by the time + * the function returns. Make sure it doesn't go away + * underneath us. + */ + kernfs_get(pos); + + /* + * Drain iff @kn was activated. This avoids draining and + * its lockdep annotations for nodes which have never been + * activated and allows embedding kernfs_remove() in create + * error paths without worrying about draining. + */ + if (kn->flags & KERNFS_ACTIVATED) + kernfs_drain(pos); + else + WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); + + /* + * kernfs_unlink_sibling() succeeds once per node. Use it + * to decide who's responsible for cleanups. + */ + if (!pos->parent || kernfs_unlink_sibling(pos)) { + struct kernfs_iattrs *ps_iattr = + pos->parent ? pos->parent->iattr : NULL; + + /* update timestamps on the parent */ + if (ps_iattr) { + ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME; + ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME; + } + + kernfs_put(pos); + } + + kernfs_put(pos); + } while (pos != kn); +} + +/** + * kernfs_remove - remove a kernfs_node recursively + * @kn: the kernfs_node to remove + * + * Remove @kn along with all its subdirectories and files. + */ +void kernfs_remove(struct kernfs_node *kn) +{ + mutex_lock(&kernfs_mutex); + __kernfs_remove(kn); + mutex_unlock(&kernfs_mutex); +} + +/** + * kernfs_break_active_protection - break out of active protection + * @kn: the self kernfs_node + * + * The caller must be running off of a kernfs operation which is invoked + * with an active reference - e.g. one of kernfs_ops. Each invocation of + * this function must also be matched with an invocation of + * kernfs_unbreak_active_protection(). + * + * This function releases the active reference of @kn the caller is + * holding. Once this function is called, @kn may be removed at any point + * and the caller is solely responsible for ensuring that the objects it + * dereferences are accessible. + */ +void kernfs_break_active_protection(struct kernfs_node *kn) +{ + /* + * Take out ourself out of the active ref dependency chain. If + * we're called without an active ref, lockdep will complain. + */ + kernfs_put_active(kn); +} + +/** + * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() + * @kn: the self kernfs_node + * + * If kernfs_break_active_protection() was called, this function must be + * invoked before finishing the kernfs operation. Note that while this + * function restores the active reference, it doesn't and can't actually + * restore the active protection - @kn may already or be in the process of + * being removed. Once kernfs_break_active_protection() is invoked, that + * protection is irreversibly gone for the kernfs operation instance. + * + * While this function may be called at any point after + * kernfs_break_active_protection() is invoked, its most useful location + * would be right before the enclosing kernfs operation returns. + */ +void kernfs_unbreak_active_protection(struct kernfs_node *kn) +{ + /* + * @kn->active could be in any state; however, the increment we do + * here will be undone as soon as the enclosing kernfs operation + * finishes and this temporary bump can't break anything. If @kn + * is alive, nothing changes. If @kn is being deactivated, the + * soon-to-follow put will either finish deactivation or restore + * deactivated state. If @kn is already removed, the temporary + * bump is guaranteed to be gone before @kn is released. + */ + atomic_inc(&kn->active); + if (kernfs_lockdep(kn)) + rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); +} + +/** + * kernfs_remove_self - remove a kernfs_node from its own method + * @kn: the self kernfs_node to remove + * + * The caller must be running off of a kernfs operation which is invoked + * with an active reference - e.g. one of kernfs_ops. This can be used to + * implement a file operation which deletes itself. + * + * For example, the "delete" file for a sysfs device directory can be + * implemented by invoking kernfs_remove_self() on the "delete" file + * itself. This function breaks the circular dependency of trying to + * deactivate self while holding an active ref itself. It isn't necessary + * to modify the usual removal path to use kernfs_remove_self(). The + * "delete" implementation can simply invoke kernfs_remove_self() on self + * before proceeding with the usual removal path. kernfs will ignore later + * kernfs_remove() on self. + * + * kernfs_remove_self() can be called multiple times concurrently on the + * same kernfs_node. Only the first one actually performs removal and + * returns %true. All others will wait until the kernfs operation which + * won self-removal finishes and return %false. Note that the losers wait + * for the completion of not only the winning kernfs_remove_self() but also + * the whole kernfs_ops which won the arbitration. This can be used to + * guarantee, for example, all concurrent writes to a "delete" file to + * finish only after the whole operation is complete. + */ +bool kernfs_remove_self(struct kernfs_node *kn) +{ + bool ret; + + mutex_lock(&kernfs_mutex); + kernfs_break_active_protection(kn); + + /* + * SUICIDAL is used to arbitrate among competing invocations. Only + * the first one will actually perform removal. When the removal + * is complete, SUICIDED is set and the active ref is restored + * while holding kernfs_mutex. The ones which lost arbitration + * waits for SUICDED && drained which can happen only after the + * enclosing kernfs operation which executed the winning instance + * of kernfs_remove_self() finished. + */ + if (!(kn->flags & KERNFS_SUICIDAL)) { + kn->flags |= KERNFS_SUICIDAL; + __kernfs_remove(kn); + kn->flags |= KERNFS_SUICIDED; + ret = true; + } else { + wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; + DEFINE_WAIT(wait); + + while (true) { + prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); + + if ((kn->flags & KERNFS_SUICIDED) && + atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) + break; + + mutex_unlock(&kernfs_mutex); + schedule(); + mutex_lock(&kernfs_mutex); + } + finish_wait(waitq, &wait); + WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); + ret = false; + } + + /* + * This must be done while holding kernfs_mutex; otherwise, waiting + * for SUICIDED && deactivated could finish prematurely. + */ + kernfs_unbreak_active_protection(kn); + + mutex_unlock(&kernfs_mutex); + return ret; +} + +/** + * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it + * @parent: parent of the target + * @name: name of the kernfs_node to remove + * @ns: namespace tag of the kernfs_node to remove + * + * Look for the kernfs_node with @name and @ns under @parent and remove it. + * Returns 0 on success, -ENOENT if such entry doesn't exist. + */ +int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, + const void *ns) +{ + struct kernfs_node *kn; + + if (!parent) { + WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", + name); + return -ENOENT; + } + + mutex_lock(&kernfs_mutex); + + kn = kernfs_find_ns(parent, name, ns); + if (kn) + __kernfs_remove(kn); + + mutex_unlock(&kernfs_mutex); + + if (kn) + return 0; + else + return -ENOENT; +} + +/** + * kernfs_rename_ns - move and rename a kernfs_node + * @kn: target node + * @new_parent: new parent to put @sd under + * @new_name: new name + * @new_ns: new namespace tag + */ +int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, + const char *new_name, const void *new_ns) +{ + int error; + + mutex_lock(&kernfs_mutex); + + error = -ENOENT; + if (!kernfs_active(kn) || !kernfs_active(new_parent)) + goto out; + + error = 0; + if ((kn->parent == new_parent) && (kn->ns == new_ns) && + (strcmp(kn->name, new_name) == 0)) + goto out; /* nothing to rename */ + + error = -EEXIST; + if (kernfs_find_ns(new_parent, new_name, new_ns)) + goto out; + + /* rename kernfs_node */ + if (strcmp(kn->name, new_name) != 0) { + error = -ENOMEM; + new_name = kstrdup(new_name, GFP_KERNEL); + if (!new_name) + goto out; + + if (kn->flags & KERNFS_STATIC_NAME) + kn->flags &= ~KERNFS_STATIC_NAME; + else + kfree(kn->name); + + kn->name = new_name; + } + + /* + * Move to the appropriate place in the appropriate directories rbtree. + */ + kernfs_unlink_sibling(kn); + kernfs_get(new_parent); + kernfs_put(kn->parent); + kn->ns = new_ns; + kn->hash = kernfs_name_hash(kn->name, kn->ns); + kn->parent = new_parent; + kernfs_link_sibling(kn); + + error = 0; + out: + mutex_unlock(&kernfs_mutex); + return error; +} + +/* Relationship between s_mode and the DT_xxx types */ +static inline unsigned char dt_type(struct kernfs_node *kn) +{ + return (kn->mode >> 12) & 15; +} + +static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) +{ + kernfs_put(filp->private_data); + return 0; +} + +static struct kernfs_node *kernfs_dir_pos(const void *ns, + struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) +{ + if (pos) { + int valid = kernfs_active(pos) && + pos->parent == parent && hash == pos->hash; + kernfs_put(pos); + if (!valid) + pos = NULL; + } + if (!pos && (hash > 1) && (hash < INT_MAX)) { + struct rb_node *node = parent->dir.children.rb_node; + while (node) { + pos = rb_to_kn(node); + + if (hash < pos->hash) + node = node->rb_left; + else if (hash > pos->hash) + node = node->rb_right; + else + break; + } + } + /* Skip over entries which are dying/dead or in the wrong namespace */ + while (pos && (!kernfs_active(pos) || pos->ns != ns)) { + struct rb_node *node = rb_next(&pos->rb); + if (!node) + pos = NULL; + else + pos = rb_to_kn(node); + } + return pos; +} + +static struct kernfs_node *kernfs_dir_next_pos(const void *ns, + struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) +{ + pos = kernfs_dir_pos(ns, parent, ino, pos); + if (pos) + do { + struct rb_node *node = rb_next(&pos->rb); + if (!node) + pos = NULL; + else + pos = rb_to_kn(node); + } while (pos && (!kernfs_active(pos) || pos->ns != ns)); + return pos; +} + +static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) +{ + struct dentry *dentry = file->f_path.dentry; + struct kernfs_node *parent = dentry->d_fsdata; + struct kernfs_node *pos = file->private_data; + const void *ns = NULL; + + if (!dir_emit_dots(file, ctx)) + return 0; + mutex_lock(&kernfs_mutex); + + if (kernfs_ns_enabled(parent)) + ns = kernfs_info(dentry->d_sb)->ns; + + for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); + pos; + pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { + const char *name = pos->name; + unsigned int type = dt_type(pos); + int len = strlen(name); + ino_t ino = pos->ino; + + ctx->pos = pos->hash; + file->private_data = pos; + kernfs_get(pos); + + mutex_unlock(&kernfs_mutex); + if (!dir_emit(ctx, name, len, ino, type)) + return 0; + mutex_lock(&kernfs_mutex); + } + mutex_unlock(&kernfs_mutex); + file->private_data = NULL; + ctx->pos = INT_MAX; + return 0; +} + +static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset, + int whence) +{ + struct inode *inode = file_inode(file); + loff_t ret; + + mutex_lock(&inode->i_mutex); + ret = generic_file_llseek(file, offset, whence); + mutex_unlock(&inode->i_mutex); + + return ret; +} + +const struct file_operations kernfs_dir_fops = { + .read = generic_read_dir, + .iterate = kernfs_fop_readdir, + .release = kernfs_dir_fop_release, + .llseek = kernfs_dir_fop_llseek, +}; diff --git a/drivers/base/core.c b/drivers/base/core.c index 2b56717..4195364 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -571,6 +571,23 @@ void device_remove_file(struct device *dev, EXPORT_SYMBOL_GPL(device_remove_file); /** + * device_remove_file_self - remove sysfs attribute file from its own method. + * @dev: device. + * @attr: device attribute descriptor. + * + * See kernfs_remove_self() for details. + */ +bool device_remove_file_self(struct device *dev, + const struct device_attribute *attr) +{ + if (dev) + return sysfs_remove_file_self(&dev->kobj, &attr->attr); + else + return false; +} +EXPORT_SYMBOL_GPL(device_remove_file_self); + +/** * device_create_bin_file - create sysfs binary attribute file for device. * @dev: device. * @attr: device binary attribute descriptor. @@ -598,39 +615,6 @@ void device_remove_bin_file(struct device *dev, } EXPORT_SYMBOL_GPL(device_remove_bin_file); -/** - * device_schedule_callback_owner - helper to schedule a callback for a device - * @dev: device. - * @func: callback function to invoke later. - * @owner: module owning the callback routine - * - * Attribute methods must not unregister themselves or their parent device - * (which would amount to the same thing). Attempts to do so will deadlock, - * since unregistration is mutually exclusive with driver callbacks. - * - * Instead methods can call this routine, which will attempt to allocate - * and schedule a workqueue request to call back @func with @dev as its - * argument in the workqueue's process context. @dev will be pinned until - * @func returns. - * - * This routine is usually called via the inline device_schedule_callback(), - * which automatically sets @owner to THIS_MODULE. - * - * Returns 0 if the request was submitted, -ENOMEM if storage could not - * be allocated, -ENODEV if a reference to @owner isn't available. - * - * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an - * underlying sysfs routine (since it is intended for use by attribute - * methods), and if sysfs isn't available you'll get nothing but -ENOSYS. - */ -int device_schedule_callback_owner(struct device *dev, - void (*func)(struct device *), struct module *owner) -{ - return sysfs_schedule_callback(&dev->kobj, - (void (*)(void *)) func, dev, owner); -} -EXPORT_SYMBOL_GPL(device_schedule_callback_owner); - static void klist_children_get(struct klist_node *n) { struct device_private *p = to_device_private_parent(n); diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index 1e16cbd..cfe1d8b 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -251,9 +251,8 @@ EXPORT_SYMBOL_GPL(dma_buf_put); * @dmabuf: [in] buffer to attach device to. * @dev: [in] device to be attached. * - * Returns struct dma_buf_attachment * for this attachment; may return negative - * error codes. - * + * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on + * error. */ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, struct device *dev) @@ -319,9 +318,8 @@ EXPORT_SYMBOL_GPL(dma_buf_detach); * @attach: [in] attachment whose scatterlist is to be returned * @direction: [in] direction of DMA transfer * - * Returns sg_table containing the scatterlist to be returned; may return NULL - * or ERR_PTR. - * + * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR + * on error. */ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, enum dma_data_direction direction) @@ -334,6 +332,8 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, return ERR_PTR(-EINVAL); sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); + if (!sg_table) + sg_table = ERR_PTR(-ENOMEM); return sg_table; } @@ -544,6 +544,8 @@ EXPORT_SYMBOL_GPL(dma_buf_mmap); * These calls are optional in drivers. The intended use for them * is for mapping objects linear in kernel space for high use objects. * Please attempt to use kmap/kunmap before thinking about these interfaces. + * + * Returns NULL on error. */ void *dma_buf_vmap(struct dma_buf *dmabuf) { @@ -566,7 +568,9 @@ void *dma_buf_vmap(struct dma_buf *dmabuf) BUG_ON(dmabuf->vmap_ptr); ptr = dmabuf->ops->vmap(dmabuf); - if (IS_ERR_OR_NULL(ptr)) + if (WARN_ON_ONCE(IS_ERR(ptr))) + ptr = NULL; + if (!ptr) goto out_unlock; dmabuf->vmap_ptr = ptr; diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 56805c3..bb516fd 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -471,7 +471,7 @@ struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev, get_dma_buf(dma_buf); sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL); - if (IS_ERR_OR_NULL(sgt)) { + if (IS_ERR(sgt)) { ret = PTR_ERR(sgt); goto fail_detach; } diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c index 59827cc..c786cd4 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c @@ -224,7 +224,7 @@ struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev, get_dma_buf(dma_buf); sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL); - if (IS_ERR_OR_NULL(sgt)) { + if (IS_ERR(sgt)) { ret = PTR_ERR(sgt); goto err_buf_detach; } diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 33d3871d..880be07 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -719,7 +719,7 @@ static int vb2_dc_map_dmabuf(void *mem_priv) /* get the associated scatterlist for this buffer */ sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); - if (IS_ERR_OR_NULL(sgt)) { + if (IS_ERR(sgt)) { pr_err("Error getting dmabuf scatterlist\n"); return -EINVAL; } diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 276ef9c..4e0acef 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -351,28 +351,17 @@ static struct device_attribute dev_rescan_attr = __ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, dev_rescan_store); -static void remove_callback(struct device *dev) -{ - pci_stop_and_remove_bus_device_locked(to_pci_dev(dev)); -} - static ssize_t -remove_store(struct device *dev, struct device_attribute *dummy, +remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { - int ret = 0; unsigned long val; if (kstrtoul(buf, 0, &val) < 0) return -EINVAL; - /* An attribute cannot be unregistered by one of its own methods, - * so we have to use this roundabout approach. - */ - if (val) - ret = device_schedule_callback(dev, remove_callback); - if (ret) - count = ret; + if (val && device_remove_file_self(dev, attr)) + pci_stop_and_remove_bus_device_locked(to_pci_dev(dev)); return count; } static struct device_attribute dev_remove_attr = __ATTR(remove, diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index ebf41e2..ee0e85a 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -304,12 +304,6 @@ dcssblk_load_segment(char *name, struct segment_info **seg_info) return rc; } -static void dcssblk_unregister_callback(struct device *dev) -{ - device_unregister(dev); - put_device(dev); -} - /* * device attribute for switching shared/nonshared (exclusive) * operation (show + store) @@ -397,7 +391,13 @@ removeseg: blk_cleanup_queue(dev_info->dcssblk_queue); dev_info->gd->queue = NULL; put_disk(dev_info->gd); - rc = device_schedule_callback(dev, dcssblk_unregister_callback); + up_write(&dcssblk_devices_sem); + + if (device_remove_file_self(dev, attr)) { + device_unregister(dev); + put_device(dev); + } + return rc; out: up_write(&dcssblk_devices_sem); return rc; diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c index fd3367a1..dfd7bc6 100644 --- a/drivers/s390/cio/ccwgroup.c +++ b/drivers/s390/cio/ccwgroup.c @@ -168,14 +168,12 @@ static ssize_t ccwgroup_online_show(struct device *dev, * Provide an 'ungroup' attribute so the user can remove group devices no * longer needed or accidentially created. Saves memory :) */ -static void ccwgroup_ungroup_callback(struct device *dev) +static void ccwgroup_ungroup(struct ccwgroup_device *gdev) { - struct ccwgroup_device *gdev = to_ccwgroupdev(dev); - mutex_lock(&gdev->reg_mutex); if (device_is_registered(&gdev->dev)) { __ccwgroup_remove_symlinks(gdev); - device_unregister(dev); + device_unregister(&gdev->dev); __ccwgroup_remove_cdev_refs(gdev); } mutex_unlock(&gdev->reg_mutex); @@ -195,10 +193,9 @@ static ssize_t ccwgroup_ungroup_store(struct device *dev, rc = -EINVAL; goto out; } - /* Note that we cannot unregister the device from one of its - * attribute methods, so we have to use this roundabout approach. - */ - rc = device_schedule_callback(dev, ccwgroup_ungroup_callback); + + if (device_remove_file_self(dev, attr)) + ccwgroup_ungroup(gdev); out: if (rc) { if (rc != -EAGAIN) @@ -224,6 +221,14 @@ static const struct attribute_group *ccwgroup_attr_groups[] = { NULL, }; +static void ccwgroup_ungroup_workfn(struct work_struct *work) +{ + struct ccwgroup_device *gdev = + container_of(work, struct ccwgroup_device, ungroup_work); + + ccwgroup_ungroup(gdev); +} + static void ccwgroup_release(struct device *dev) { kfree(to_ccwgroupdev(dev)); @@ -323,6 +328,7 @@ int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv, atomic_set(&gdev->onoff, 0); mutex_init(&gdev->reg_mutex); mutex_lock(&gdev->reg_mutex); + INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn); gdev->count = num_devices; gdev->dev.bus = &ccwgroup_bus_type; gdev->dev.parent = parent; @@ -404,10 +410,10 @@ EXPORT_SYMBOL(ccwgroup_create_dev); static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action, void *data) { - struct device *dev = data; + struct ccwgroup_device *gdev = to_ccwgroupdev(data); if (action == BUS_NOTIFY_UNBIND_DRIVER) - device_schedule_callback(dev, ccwgroup_ungroup_callback); + schedule_work(&gdev->ungroup_work); return NOTIFY_OK; } diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 9117d0b..8ead24c 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -649,23 +649,12 @@ store_rescan_field (struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR(rescan, S_IWUSR, NULL, store_rescan_field); -static void sdev_store_delete_callback(struct device *dev) -{ - scsi_remove_device(to_scsi_device(dev)); -} - static ssize_t sdev_store_delete(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { - int rc; - - /* An attribute cannot be unregistered by one of its own methods, - * so we have to use this roundabout approach. - */ - rc = device_schedule_callback(dev, sdev_store_delete_callback); - if (rc) - count = rc; + if (device_remove_file_self(dev, attr)) + scsi_remove_device(to_scsi_device(dev)); return count; }; static DEVICE_ATTR(delete, S_IWUSR, NULL, sdev_store_delete); @@ -96,6 +96,7 @@ endif # BLOCK menu "Pseudo filesystems" source "fs/proc/Kconfig" +source "fs/kernfs/Kconfig" source "fs/sysfs/Kconfig" config TMPFS diff --git a/fs/Makefile b/fs/Makefile index 47ac07b..f9cb987 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -52,7 +52,8 @@ obj-$(CONFIG_FHANDLE) += fhandle.o obj-y += quota/ obj-$(CONFIG_PROC_FS) += proc/ -obj-$(CONFIG_SYSFS) += sysfs/ kernfs/ +obj-$(CONFIG_KERNFS) += kernfs/ +obj-$(CONFIG_SYSFS) += sysfs/ obj-$(CONFIG_CONFIGFS_FS) += configfs/ obj-y += devpts/ diff --git a/fs/kernfs/Kconfig b/fs/kernfs/Kconfig new file mode 100644 index 0000000..397b5f7 --- /dev/null +++ b/fs/kernfs/Kconfig @@ -0,0 +1,7 @@ +# +# KERNFS should be selected by its users +# + +config KERNFS + bool + default n diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index bd6e18b..a0f99b7 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -8,6 +8,7 @@ * This file is released under the GPLv2. */ +#include <linux/sched.h> #include <linux/fs.h> #include <linux/namei.h> #include <linux/idr.h> @@ -18,9 +19,161 @@ #include "kernfs-internal.h" DEFINE_MUTEX(kernfs_mutex); +static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */ +static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */ #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) +static bool kernfs_active(struct kernfs_node *kn) +{ + lockdep_assert_held(&kernfs_mutex); + return atomic_read(&kn->active) >= 0; +} + +static bool kernfs_lockdep(struct kernfs_node *kn) +{ +#ifdef CONFIG_DEBUG_LOCK_ALLOC + return kn->flags & KERNFS_LOCKDEP; +#else + return false; +#endif +} + +static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen) +{ + return strlcpy(buf, kn->parent ? kn->name : "/", buflen); +} + +static char * __must_check kernfs_path_locked(struct kernfs_node *kn, char *buf, + size_t buflen) +{ + char *p = buf + buflen; + int len; + + *--p = '\0'; + + do { + len = strlen(kn->name); + if (p - buf < len + 1) { + buf[0] = '\0'; + p = NULL; + break; + } + p -= len; + memcpy(p, kn->name, len); + *--p = '/'; + kn = kn->parent; + } while (kn && kn->parent); + + return p; +} + +/** + * kernfs_name - obtain the name of a given node + * @kn: kernfs_node of interest + * @buf: buffer to copy @kn's name into + * @buflen: size of @buf + * + * Copies the name of @kn into @buf of @buflen bytes. The behavior is + * similar to strlcpy(). It returns the length of @kn's name and if @buf + * isn't long enough, it's filled upto @buflen-1 and nul terminated. + * + * This function can be called from any context. + */ +int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) +{ + unsigned long flags; + int ret; + + spin_lock_irqsave(&kernfs_rename_lock, flags); + ret = kernfs_name_locked(kn, buf, buflen); + spin_unlock_irqrestore(&kernfs_rename_lock, flags); + return ret; +} + +/** + * kernfs_path - build full path of a given node + * @kn: kernfs_node of interest + * @buf: buffer to copy @kn's name into + * @buflen: size of @buf + * + * Builds and returns the full path of @kn in @buf of @buflen bytes. The + * path is built from the end of @buf so the returned pointer usually + * doesn't match @buf. If @buf isn't long enough, @buf is nul terminated + * and %NULL is returned. + */ +char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen) +{ + unsigned long flags; + char *p; + + spin_lock_irqsave(&kernfs_rename_lock, flags); + p = kernfs_path_locked(kn, buf, buflen); + spin_unlock_irqrestore(&kernfs_rename_lock, flags); + return p; +} + +/** + * pr_cont_kernfs_name - pr_cont name of a kernfs_node + * @kn: kernfs_node of interest + * + * This function can be called from any context. + */ +void pr_cont_kernfs_name(struct kernfs_node *kn) +{ + unsigned long flags; + + spin_lock_irqsave(&kernfs_rename_lock, flags); + + kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf)); + pr_cont("%s", kernfs_pr_cont_buf); + + spin_unlock_irqrestore(&kernfs_rename_lock, flags); +} + +/** + * pr_cont_kernfs_path - pr_cont path of a kernfs_node + * @kn: kernfs_node of interest + * + * This function can be called from any context. + */ +void pr_cont_kernfs_path(struct kernfs_node *kn) +{ + unsigned long flags; + char *p; + + spin_lock_irqsave(&kernfs_rename_lock, flags); + + p = kernfs_path_locked(kn, kernfs_pr_cont_buf, + sizeof(kernfs_pr_cont_buf)); + if (p) + pr_cont("%s", p); + else + pr_cont("<name too long>"); + + spin_unlock_irqrestore(&kernfs_rename_lock, flags); +} + +/** + * kernfs_get_parent - determine the parent node and pin it + * @kn: kernfs_node of interest + * + * Determines @kn's parent, pins and returns it. This function can be + * called from any context. + */ +struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) +{ + struct kernfs_node *parent; + unsigned long flags; + + spin_lock_irqsave(&kernfs_rename_lock, flags); + parent = kn->parent; + kernfs_get(parent); + spin_unlock_irqrestore(&kernfs_rename_lock, flags); + + return parent; +} + /** * kernfs_name_hash * @name: Null terminated string to hash @@ -105,18 +258,24 @@ static int kernfs_link_sibling(struct kernfs_node *kn) * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree * @kn: kernfs_node of interest * - * Unlink @kn from its sibling rbtree which starts from - * kn->parent->dir.children. + * Try to unlink @kn from its sibling rbtree which starts from + * kn->parent->dir.children. Returns %true if @kn was actually + * removed, %false if @kn wasn't on the rbtree. * * Locking: * mutex_lock(kernfs_mutex) */ -static void kernfs_unlink_sibling(struct kernfs_node *kn) +static bool kernfs_unlink_sibling(struct kernfs_node *kn) { + if (RB_EMPTY_NODE(&kn->rb)) + return false; + if (kernfs_type(kn) == KERNFS_DIR) kn->parent->dir.subdirs--; rb_erase(&kn->rb, &kn->parent->dir.children); + RB_CLEAR_NODE(&kn->rb); + return true; } /** @@ -137,7 +296,7 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) if (!atomic_inc_unless_negative(&kn->active)) return NULL; - if (kn->flags & KERNFS_LOCKDEP) + if (kernfs_lockdep(kn)) rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); return kn; } @@ -151,59 +310,57 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) */ void kernfs_put_active(struct kernfs_node *kn) { + struct kernfs_root *root = kernfs_root(kn); int v; if (unlikely(!kn)) return; - if (kn->flags & KERNFS_LOCKDEP) + if (kernfs_lockdep(kn)) rwsem_release(&kn->dep_map, 1, _RET_IP_); v = atomic_dec_return(&kn->active); if (likely(v != KN_DEACTIVATED_BIAS)) return; - /* - * atomic_dec_return() is a mb(), we'll always see the updated - * kn->u.completion. - */ - complete(kn->u.completion); + wake_up_all(&root->deactivate_waitq); } /** - * kernfs_deactivate - deactivate kernfs_node - * @kn: kernfs_node to deactivate + * kernfs_drain - drain kernfs_node + * @kn: kernfs_node to drain * - * Deny new active references and drain existing ones. + * Drain existing usages and nuke all existing mmaps of @kn. Mutiple + * removers may invoke this function concurrently on @kn and all will + * return after draining is complete. */ -static void kernfs_deactivate(struct kernfs_node *kn) +static void kernfs_drain(struct kernfs_node *kn) + __releases(&kernfs_mutex) __acquires(&kernfs_mutex) { - DECLARE_COMPLETION_ONSTACK(wait); - int v; + struct kernfs_root *root = kernfs_root(kn); - BUG_ON(!(kn->flags & KERNFS_REMOVED)); - - if (!(kernfs_type(kn) & KERNFS_ACTIVE_REF)) - return; + lockdep_assert_held(&kernfs_mutex); + WARN_ON_ONCE(kernfs_active(kn)); - kn->u.completion = (void *)&wait; + mutex_unlock(&kernfs_mutex); - if (kn->flags & KERNFS_LOCKDEP) + if (kernfs_lockdep(kn)) { rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); - /* atomic_add_return() is a mb(), put_active() will always see - * the updated kn->u.completion. - */ - v = atomic_add_return(KN_DEACTIVATED_BIAS, &kn->active); - - if (v != KN_DEACTIVATED_BIAS) { - if (kn->flags & KERNFS_LOCKDEP) + if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) lock_contended(&kn->dep_map, _RET_IP_); - wait_for_completion(&wait); } - if (kn->flags & KERNFS_LOCKDEP) { + /* but everyone should wait for draining */ + wait_event(root->deactivate_waitq, + atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); + + if (kernfs_lockdep(kn)) { lock_acquired(&kn->dep_map, _RET_IP_); rwsem_release(&kn->dep_map, 1, _RET_IP_); } + + kernfs_unmap_bin_file(kn); + + mutex_lock(&kernfs_mutex); } /** @@ -234,13 +391,15 @@ void kernfs_put(struct kernfs_node *kn) return; root = kernfs_root(kn); repeat: - /* Moving/renaming is always done while holding reference. + /* + * Moving/renaming is always done while holding reference. * kn->parent won't change beneath us. */ parent = kn->parent; - WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n", - parent ? parent->name : "", kn->name); + WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, + "kernfs_put: %s/%s: released with incorrect active_ref %d\n", + parent ? parent->name : "", kn->name, atomic_read(&kn->active)); if (kernfs_type(kn) == KERNFS_LINK) kernfs_put(kn->symlink.target_kn); @@ -282,8 +441,8 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) kn = dentry->d_fsdata; mutex_lock(&kernfs_mutex); - /* The kernfs node has been deleted */ - if (kn->flags & KERNFS_REMOVED) + /* The kernfs node has been deactivated */ + if (!kernfs_active(kn)) goto out_bad; /* The kernfs node has been moved? */ @@ -328,6 +487,24 @@ const struct dentry_operations kernfs_dops = { .d_release = kernfs_dop_release, }; +/** + * kernfs_node_from_dentry - determine kernfs_node associated with a dentry + * @dentry: the dentry in question + * + * Return the kernfs_node associated with @dentry. If @dentry is not a + * kernfs one, %NULL is returned. + * + * While the returned kernfs_node will stay accessible as long as @dentry + * is accessible, the returned node can be in any state and the caller is + * fully responsible for determining what's accessible. + */ +struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) +{ + if (dentry->d_op == &kernfs_dops) + return dentry->d_fsdata; + return NULL; +} + static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, const char *name, umode_t mode, unsigned flags) @@ -352,11 +529,12 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, kn->ino = ret; atomic_set(&kn->count, 1); - atomic_set(&kn->active, 0); + atomic_set(&kn->active, KN_DEACTIVATED_BIAS); + RB_CLEAR_NODE(&kn->rb); kn->name = name; kn->mode = mode; - kn->flags = flags | KERNFS_REMOVED; + kn->flags = flags; return kn; @@ -382,69 +560,44 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, } /** - * kernfs_addrm_start - prepare for kernfs_node add/remove - * @acxt: pointer to kernfs_addrm_cxt to be used - * - * This function is called when the caller is about to add or remove - * kernfs_node. This function acquires kernfs_mutex. @acxt is used - * to keep and pass context to other addrm functions. - * - * LOCKING: - * Kernel thread context (may sleep). kernfs_mutex is locked on - * return. - */ -void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt) - __acquires(kernfs_mutex) -{ - memset(acxt, 0, sizeof(*acxt)); - - mutex_lock(&kernfs_mutex); -} - -/** * kernfs_add_one - add kernfs_node to parent without warning - * @acxt: addrm context to use * @kn: kernfs_node to be added * * The caller must already have initialized @kn->parent. This * function increments nlink of the parent's inode if @kn is a * directory and link into the children list of the parent. * - * This function should be called between calls to - * kernfs_addrm_start() and kernfs_addrm_finish() and should be passed - * the same @acxt as passed to kernfs_addrm_start(). - * - * LOCKING: - * Determined by kernfs_addrm_start(). - * * RETURNS: * 0 on success, -EEXIST if entry with the given name already * exists. */ -int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn) +int kernfs_add_one(struct kernfs_node *kn) { struct kernfs_node *parent = kn->parent; - bool has_ns = kernfs_ns_enabled(parent); struct kernfs_iattrs *ps_iattr; + bool has_ns; int ret; - if (has_ns != (bool)kn->ns) { - WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", - has_ns ? "required" : "invalid", parent->name, kn->name); - return -EINVAL; - } + mutex_lock(&kernfs_mutex); + + ret = -EINVAL; + has_ns = kernfs_ns_enabled(parent); + if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", + has_ns ? "required" : "invalid", parent->name, kn->name)) + goto out_unlock; if (kernfs_type(parent) != KERNFS_DIR) - return -EINVAL; + goto out_unlock; - if (parent->flags & KERNFS_REMOVED) - return -ENOENT; + ret = -ENOENT; + if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) + goto out_unlock; kn->hash = kernfs_name_hash(kn->name, kn->ns); ret = kernfs_link_sibling(kn); if (ret) - return ret; + goto out_unlock; /* Update timestamps on the parent */ ps_iattr = parent->iattr; @@ -453,82 +606,22 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn) ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; } - /* Mark the entry added into directory tree */ - kn->flags &= ~KERNFS_REMOVED; - - return 0; -} - -/** - * kernfs_remove_one - remove kernfs_node from parent - * @acxt: addrm context to use - * @kn: kernfs_node to be removed - * - * Mark @kn removed and drop nlink of parent inode if @kn is a - * directory. @kn is unlinked from the children list. - * - * This function should be called between calls to - * kernfs_addrm_start() and kernfs_addrm_finish() and should be - * passed the same @acxt as passed to kernfs_addrm_start(). - * - * LOCKING: - * Determined by kernfs_addrm_start(). - */ -static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt, - struct kernfs_node *kn) -{ - struct kernfs_iattrs *ps_iattr; + mutex_unlock(&kernfs_mutex); /* - * Removal can be called multiple times on the same node. Only the - * first invocation is effective and puts the base ref. + * Activate the new node unless CREATE_DEACTIVATED is requested. + * If not activated here, the kernfs user is responsible for + * activating the node with kernfs_activate(). A node which hasn't + * been activated is not visible to userland and its removal won't + * trigger deactivation. */ - if (kn->flags & KERNFS_REMOVED) - return; - - if (kn->parent) { - kernfs_unlink_sibling(kn); - - /* Update timestamps on the parent */ - ps_iattr = kn->parent->iattr; - if (ps_iattr) { - ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME; - ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME; - } - } - - kn->flags |= KERNFS_REMOVED; - kn->u.removed_list = acxt->removed; - acxt->removed = kn; -} + if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) + kernfs_activate(kn); + return 0; -/** - * kernfs_addrm_finish - finish up kernfs_node add/remove - * @acxt: addrm context to finish up - * - * Finish up kernfs_node add/remove. Resources acquired by - * kernfs_addrm_start() are released and removed kernfs_nodes are - * cleaned up. - * - * LOCKING: - * kernfs_mutex is released. - */ -void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt) - __releases(kernfs_mutex) -{ - /* release resources acquired by kernfs_addrm_start() */ +out_unlock: mutex_unlock(&kernfs_mutex); - - /* kill removed kernfs_nodes */ - while (acxt->removed) { - struct kernfs_node *kn = acxt->removed; - - acxt->removed = kn->u.removed_list; - - kernfs_deactivate(kn); - kernfs_unmap_bin_file(kn); - kernfs_put(kn); - } + return ret; } /** @@ -599,13 +692,15 @@ EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); /** * kernfs_create_root - create a new kernfs hierarchy - * @kdops: optional directory syscall operations for the hierarchy + * @scops: optional syscall operations for the hierarchy + * @flags: KERNFS_ROOT_* flags * @priv: opaque data associated with the new directory * * Returns the root of the new hierarchy on success, ERR_PTR() value on * failure. */ -struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv) +struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, + unsigned int flags, void *priv) { struct kernfs_root *root; struct kernfs_node *kn; @@ -624,12 +719,16 @@ struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv) return ERR_PTR(-ENOMEM); } - kn->flags &= ~KERNFS_REMOVED; kn->priv = priv; kn->dir.root = root; - root->dir_ops = kdops; + root->syscall_ops = scops; + root->flags = flags; root->kn = kn; + init_waitqueue_head(&root->deactivate_waitq); + + if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) + kernfs_activate(kn); return root; } @@ -660,7 +759,6 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, const char *name, umode_t mode, void *priv, const void *ns) { - struct kernfs_addrm_cxt acxt; struct kernfs_node *kn; int rc; @@ -674,10 +772,7 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, kn->priv = priv; /* link in */ - kernfs_addrm_start(&acxt); - rc = kernfs_add_one(&acxt, kn); - kernfs_addrm_finish(&acxt); - + rc = kernfs_add_one(kn); if (!rc) return kn; @@ -703,7 +798,7 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir, kn = kernfs_find_ns(parent, dentry->d_name.name, ns); /* no such entry */ - if (!kn) { + if (!kn || !kernfs_active(kn)) { ret = NULL; goto out_unlock; } @@ -728,23 +823,37 @@ static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { struct kernfs_node *parent = dir->i_private; - struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops; + struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; + int ret; - if (!kdops || !kdops->mkdir) + if (!scops || !scops->mkdir) return -EPERM; - return kdops->mkdir(parent, dentry->d_name.name, mode); + if (!kernfs_get_active(parent)) + return -ENODEV; + + ret = scops->mkdir(parent, dentry->d_name.name, mode); + + kernfs_put_active(parent); + return ret; } static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) { struct kernfs_node *kn = dentry->d_fsdata; - struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops; + struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; + int ret; - if (!kdops || !kdops->rmdir) + if (!scops || !scops->rmdir) return -EPERM; - return kdops->rmdir(kn); + if (!kernfs_get_active(kn)) + return -ENODEV; + + ret = scops->rmdir(kn); + + kernfs_put_active(kn); + return ret; } static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, @@ -752,12 +861,25 @@ static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, { struct kernfs_node *kn = old_dentry->d_fsdata; struct kernfs_node *new_parent = new_dir->i_private; - struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops; + struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; + int ret; - if (!kdops || !kdops->rename) + if (!scops || !scops->rename) return -EPERM; - return kdops->rename(kn, new_parent, new_dentry->d_name.name); + if (!kernfs_get_active(kn)) + return -ENODEV; + + if (!kernfs_get_active(new_parent)) { + kernfs_put_active(kn); + return -ENODEV; + } + + ret = scops->rename(kn, new_parent, new_dentry->d_name.name); + + kernfs_put_active(new_parent); + kernfs_put_active(kn); + return ret; } const struct inode_operations kernfs_dir_iops = { @@ -830,23 +952,104 @@ static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, return pos->parent; } -static void __kernfs_remove(struct kernfs_addrm_cxt *acxt, - struct kernfs_node *kn) +/** + * kernfs_activate - activate a node which started deactivated + * @kn: kernfs_node whose subtree is to be activated + * + * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node + * needs to be explicitly activated. A node which hasn't been activated + * isn't visible to userland and deactivation is skipped during its + * removal. This is useful to construct atomic init sequences where + * creation of multiple nodes should either succeed or fail atomically. + * + * The caller is responsible for ensuring that this function is not called + * after kernfs_remove*() is invoked on @kn. + */ +void kernfs_activate(struct kernfs_node *kn) { - struct kernfs_node *pos, *next; + struct kernfs_node *pos; - if (!kn) + mutex_lock(&kernfs_mutex); + + pos = NULL; + while ((pos = kernfs_next_descendant_post(pos, kn))) { + if (!pos || (pos->flags & KERNFS_ACTIVATED)) + continue; + + WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb)); + WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS); + + atomic_sub(KN_DEACTIVATED_BIAS, &pos->active); + pos->flags |= KERNFS_ACTIVATED; + } + + mutex_unlock(&kernfs_mutex); +} + +static void __kernfs_remove(struct kernfs_node *kn) +{ + struct kernfs_node *pos; + + lockdep_assert_held(&kernfs_mutex); + + /* + * Short-circuit if non-root @kn has already finished removal. + * This is for kernfs_remove_self() which plays with active ref + * after removal. + */ + if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb))) return; pr_debug("kernfs %s: removing\n", kn->name); - next = NULL; + /* prevent any new usage under @kn by deactivating all nodes */ + pos = NULL; + while ((pos = kernfs_next_descendant_post(pos, kn))) + if (kernfs_active(pos)) + atomic_add(KN_DEACTIVATED_BIAS, &pos->active); + + /* deactivate and unlink the subtree node-by-node */ do { - pos = next; - next = kernfs_next_descendant_post(pos, kn); - if (pos) - kernfs_remove_one(acxt, pos); - } while (next); + pos = kernfs_leftmost_descendant(kn); + + /* + * kernfs_drain() drops kernfs_mutex temporarily and @pos's + * base ref could have been put by someone else by the time + * the function returns. Make sure it doesn't go away + * underneath us. + */ + kernfs_get(pos); + + /* + * Drain iff @kn was activated. This avoids draining and + * its lockdep annotations for nodes which have never been + * activated and allows embedding kernfs_remove() in create + * error paths without worrying about draining. + */ + if (kn->flags & KERNFS_ACTIVATED) + kernfs_drain(pos); + else + WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); + + /* + * kernfs_unlink_sibling() succeeds once per node. Use it + * to decide who's responsible for cleanups. + */ + if (!pos->parent || kernfs_unlink_sibling(pos)) { + struct kernfs_iattrs *ps_iattr = + pos->parent ? pos->parent->iattr : NULL; + + /* update timestamps on the parent */ + if (ps_iattr) { + ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME; + ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME; + } + + kernfs_put(pos); + } + + kernfs_put(pos); + } while (pos != kn); } /** @@ -857,11 +1060,140 @@ static void __kernfs_remove(struct kernfs_addrm_cxt *acxt, */ void kernfs_remove(struct kernfs_node *kn) { - struct kernfs_addrm_cxt acxt; + mutex_lock(&kernfs_mutex); + __kernfs_remove(kn); + mutex_unlock(&kernfs_mutex); +} - kernfs_addrm_start(&acxt); - __kernfs_remove(&acxt, kn); - kernfs_addrm_finish(&acxt); +/** + * kernfs_break_active_protection - break out of active protection + * @kn: the self kernfs_node + * + * The caller must be running off of a kernfs operation which is invoked + * with an active reference - e.g. one of kernfs_ops. Each invocation of + * this function must also be matched with an invocation of + * kernfs_unbreak_active_protection(). + * + * This function releases the active reference of @kn the caller is + * holding. Once this function is called, @kn may be removed at any point + * and the caller is solely responsible for ensuring that the objects it + * dereferences are accessible. + */ +void kernfs_break_active_protection(struct kernfs_node *kn) +{ + /* + * Take out ourself out of the active ref dependency chain. If + * we're called without an active ref, lockdep will complain. + */ + kernfs_put_active(kn); +} + +/** + * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() + * @kn: the self kernfs_node + * + * If kernfs_break_active_protection() was called, this function must be + * invoked before finishing the kernfs operation. Note that while this + * function restores the active reference, it doesn't and can't actually + * restore the active protection - @kn may already or be in the process of + * being removed. Once kernfs_break_active_protection() is invoked, that + * protection is irreversibly gone for the kernfs operation instance. + * + * While this function may be called at any point after + * kernfs_break_active_protection() is invoked, its most useful location + * would be right before the enclosing kernfs operation returns. + */ +void kernfs_unbreak_active_protection(struct kernfs_node *kn) +{ + /* + * @kn->active could be in any state; however, the increment we do + * here will be undone as soon as the enclosing kernfs operation + * finishes and this temporary bump can't break anything. If @kn + * is alive, nothing changes. If @kn is being deactivated, the + * soon-to-follow put will either finish deactivation or restore + * deactivated state. If @kn is already removed, the temporary + * bump is guaranteed to be gone before @kn is released. + */ + atomic_inc(&kn->active); + if (kernfs_lockdep(kn)) + rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); +} + +/** + * kernfs_remove_self - remove a kernfs_node from its own method + * @kn: the self kernfs_node to remove + * + * The caller must be running off of a kernfs operation which is invoked + * with an active reference - e.g. one of kernfs_ops. This can be used to + * implement a file operation which deletes itself. + * + * For example, the "delete" file for a sysfs device directory can be + * implemented by invoking kernfs_remove_self() on the "delete" file + * itself. This function breaks the circular dependency of trying to + * deactivate self while holding an active ref itself. It isn't necessary + * to modify the usual removal path to use kernfs_remove_self(). The + * "delete" implementation can simply invoke kernfs_remove_self() on self + * before proceeding with the usual removal path. kernfs will ignore later + * kernfs_remove() on self. + * + * kernfs_remove_self() can be called multiple times concurrently on the + * same kernfs_node. Only the first one actually performs removal and + * returns %true. All others will wait until the kernfs operation which + * won self-removal finishes and return %false. Note that the losers wait + * for the completion of not only the winning kernfs_remove_self() but also + * the whole kernfs_ops which won the arbitration. This can be used to + * guarantee, for example, all concurrent writes to a "delete" file to + * finish only after the whole operation is complete. + */ +bool kernfs_remove_self(struct kernfs_node *kn) +{ + bool ret; + + mutex_lock(&kernfs_mutex); + kernfs_break_active_protection(kn); + + /* + * SUICIDAL is used to arbitrate among competing invocations. Only + * the first one will actually perform removal. When the removal + * is complete, SUICIDED is set and the active ref is restored + * while holding kernfs_mutex. The ones which lost arbitration + * waits for SUICDED && drained which can happen only after the + * enclosing kernfs operation which executed the winning instance + * of kernfs_remove_self() finished. + */ + if (!(kn->flags & KERNFS_SUICIDAL)) { + kn->flags |= KERNFS_SUICIDAL; + __kernfs_remove(kn); + kn->flags |= KERNFS_SUICIDED; + ret = true; + } else { + wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; + DEFINE_WAIT(wait); + + while (true) { + prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); + + if ((kn->flags & KERNFS_SUICIDED) && + atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) + break; + + mutex_unlock(&kernfs_mutex); + schedule(); + mutex_lock(&kernfs_mutex); + } + finish_wait(waitq, &wait); + WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); + ret = false; + } + + /* + * This must be done while holding kernfs_mutex; otherwise, waiting + * for SUICIDED && deactivated could finish prematurely. + */ + kernfs_unbreak_active_protection(kn); + + mutex_unlock(&kernfs_mutex); + return ret; } /** @@ -876,7 +1208,6 @@ void kernfs_remove(struct kernfs_node *kn) int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, const void *ns) { - struct kernfs_addrm_cxt acxt; struct kernfs_node *kn; if (!parent) { @@ -885,13 +1216,13 @@ int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, return -ENOENT; } - kernfs_addrm_start(&acxt); + mutex_lock(&kernfs_mutex); kn = kernfs_find_ns(parent, name, ns); if (kn) - __kernfs_remove(&acxt, kn); + __kernfs_remove(kn); - kernfs_addrm_finish(&acxt); + mutex_unlock(&kernfs_mutex); if (kn) return 0; @@ -909,12 +1240,18 @@ int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, const char *new_name, const void *new_ns) { + struct kernfs_node *old_parent; + const char *old_name = NULL; int error; + /* can't move or rename root */ + if (!kn->parent) + return -EINVAL; + mutex_lock(&kernfs_mutex); error = -ENOENT; - if ((kn->flags | new_parent->flags) & KERNFS_REMOVED) + if (!kernfs_active(kn) || !kernfs_active(new_parent)) goto out; error = 0; @@ -932,13 +1269,8 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, new_name = kstrdup(new_name, GFP_KERNEL); if (!new_name) goto out; - - if (kn->flags & KERNFS_STATIC_NAME) - kn->flags &= ~KERNFS_STATIC_NAME; - else - kfree(kn->name); - - kn->name = new_name; + } else { + new_name = NULL; } /* @@ -946,12 +1278,29 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, */ kernfs_unlink_sibling(kn); kernfs_get(new_parent); - kernfs_put(kn->parent); + + /* rename_lock protects ->parent and ->name accessors */ + spin_lock_irq(&kernfs_rename_lock); + + old_parent = kn->parent; + kn->parent = new_parent; + kn->ns = new_ns; + if (new_name) { + if (!(kn->flags & KERNFS_STATIC_NAME)) + old_name = kn->name; + kn->flags &= ~KERNFS_STATIC_NAME; + kn->name = new_name; + } + + spin_unlock_irq(&kernfs_rename_lock); + kn->hash = kernfs_name_hash(kn->name, kn->ns); - kn->parent = new_parent; kernfs_link_sibling(kn); + kernfs_put(old_parent); + kfree(old_name); + error = 0; out: mutex_unlock(&kernfs_mutex); @@ -974,7 +1323,7 @@ static struct kernfs_node *kernfs_dir_pos(const void *ns, struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) { if (pos) { - int valid = !(pos->flags & KERNFS_REMOVED) && + int valid = kernfs_active(pos) && pos->parent == parent && hash == pos->hash; kernfs_put(pos); if (!valid) @@ -993,8 +1342,8 @@ static struct kernfs_node *kernfs_dir_pos(const void *ns, break; } } - /* Skip over entries in the wrong namespace */ - while (pos && pos->ns != ns) { + /* Skip over entries which are dying/dead or in the wrong namespace */ + while (pos && (!kernfs_active(pos) || pos->ns != ns)) { struct rb_node *node = rb_next(&pos->rb); if (!node) pos = NULL; @@ -1008,14 +1357,15 @@ static struct kernfs_node *kernfs_dir_next_pos(const void *ns, struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) { pos = kernfs_dir_pos(ns, parent, ino, pos); - if (pos) + if (pos) { do { struct rb_node *node = rb_next(&pos->rb); if (!node) pos = NULL; else pos = rb_to_kn(node); - } while (pos && pos->ns != ns); + } while (pos && (!kernfs_active(pos) || pos->ns != ns)); + } return pos; } diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index dbf397b..ddcb471 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -252,19 +252,9 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { struct kernfs_open_file *of = kernfs_of(file); - ssize_t len = min_t(size_t, count, PAGE_SIZE); const struct kernfs_ops *ops; - char *buf; - - buf = kmalloc(len + 1, GFP_KERNEL); - if (!buf) - return -ENOMEM; - - if (copy_from_user(buf, user_buf, len)) { - len = -EFAULT; - goto out_free; - } - buf[len] = '\0'; /* guarantee string termination */ + char *buf = NULL; + ssize_t len; /* * @of->mutex nests outside active ref and is just to ensure that @@ -273,22 +263,45 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, mutex_lock(&of->mutex); if (!kernfs_get_active(of->kn)) { mutex_unlock(&of->mutex); - len = -ENODEV; - goto out_free; + return -ENODEV; } ops = kernfs_ops(of->kn); - if (ops->write) - len = ops->write(of, buf, len, *ppos); - else + if (!ops->write) { len = -EINVAL; + goto out_unlock; + } + if (ops->atomic_write_len) { + len = count; + if (len > ops->atomic_write_len) { + len = -E2BIG; + goto out_unlock; + } + } else { + len = min_t(size_t, count, PAGE_SIZE); + } + + buf = kmalloc(len + 1, GFP_KERNEL); + if (!buf) { + len = -ENOMEM; + goto out_unlock; + } + + if (copy_from_user(buf, user_buf, len)) { + len = -EFAULT; + goto out_unlock; + } + buf[len] = '\0'; /* guarantee string termination */ + + len = ops->write(of, buf, len, *ppos); +out_unlock: kernfs_put_active(of->kn); mutex_unlock(&of->mutex); if (len > 0) *ppos += len; -out_free: + kfree(buf); return len; } @@ -820,7 +833,6 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, bool name_is_static, struct lock_class_key *key) { - struct kernfs_addrm_cxt acxt; struct kernfs_node *kn; unsigned flags; int rc; @@ -855,10 +867,7 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, if (ops->mmap) kn->flags |= KERNFS_HAS_MMAP; - kernfs_addrm_start(&acxt); - rc = kernfs_add_one(&acxt, kn); - kernfs_addrm_finish(&acxt); - + rc = kernfs_add_one(kn); if (rc) { kernfs_put(kn); return ERR_PTR(rc); diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index eb536b7..a91d7a1 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -26,7 +26,8 @@ struct kernfs_iattrs { struct simple_xattrs xattrs; }; -#define KN_DEACTIVATED_BIAS INT_MIN +/* +1 to avoid triggering overflow warning when negating it */ +#define KN_DEACTIVATED_BIAS (INT_MIN + 1) /* KERNFS_TYPE_MASK and types are defined in include/linux/kernfs.h */ @@ -45,13 +46,6 @@ static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn) } /* - * Context structure to be used while adding/removing nodes. - */ -struct kernfs_addrm_cxt { - struct kernfs_node *removed; -}; - -/* * mount.c */ struct kernfs_super_info { @@ -100,9 +94,7 @@ extern const struct inode_operations kernfs_dir_iops; struct kernfs_node *kernfs_get_active(struct kernfs_node *kn); void kernfs_put_active(struct kernfs_node *kn); -void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt); -int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn); -void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt); +int kernfs_add_one(struct kernfs_node *kn); struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, const char *name, umode_t mode, unsigned flags); diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index 0d6ce89..e5b28b0 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -19,12 +19,49 @@ struct kmem_cache *kernfs_node_cache; +static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data) +{ + struct kernfs_root *root = kernfs_info(sb)->root; + struct kernfs_syscall_ops *scops = root->syscall_ops; + + if (scops && scops->remount_fs) + return scops->remount_fs(root, flags, data); + return 0; +} + +static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry) +{ + struct kernfs_root *root = kernfs_root(dentry->d_fsdata); + struct kernfs_syscall_ops *scops = root->syscall_ops; + + if (scops && scops->show_options) + return scops->show_options(sf, root); + return 0; +} + static const struct super_operations kernfs_sops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, .evict_inode = kernfs_evict_inode, + + .remount_fs = kernfs_sop_remount_fs, + .show_options = kernfs_sop_show_options, }; +/** + * kernfs_root_from_sb - determine kernfs_root associated with a super_block + * @sb: the super_block in question + * + * Return the kernfs_root associated with @sb. If @sb is not a kernfs one, + * %NULL is returned. + */ +struct kernfs_root *kernfs_root_from_sb(struct super_block *sb) +{ + if (sb->s_op == &kernfs_sops) + return kernfs_info(sb)->root; + return NULL; +} + static int kernfs_fill_super(struct super_block *sb) { struct kernfs_super_info *info = kernfs_info(sb); diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c index 4d45705..8a19889 100644 --- a/fs/kernfs/symlink.c +++ b/fs/kernfs/symlink.c @@ -27,7 +27,6 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, struct kernfs_node *target) { struct kernfs_node *kn; - struct kernfs_addrm_cxt acxt; int error; kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK); @@ -39,10 +38,7 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, kn->symlink.target_kn = target; kernfs_get(target); /* ref owned by symlink */ - kernfs_addrm_start(&acxt); - error = kernfs_add_one(&acxt, kn); - kernfs_addrm_finish(&acxt); - + error = kernfs_add_one(kn); if (!error) return kn; diff --git a/fs/sysfs/Kconfig b/fs/sysfs/Kconfig index 8c41fea..b275601 100644 --- a/fs/sysfs/Kconfig +++ b/fs/sysfs/Kconfig @@ -1,6 +1,7 @@ config SYSFS bool "sysfs file system support" if EXPERT default y + select KERNFS help The sysfs filesystem is a virtual filesystem that the kernel uses to export internal kernel objects, their attributes, and their diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index ee0d761..0b45ff4 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -19,39 +19,18 @@ DEFINE_SPINLOCK(sysfs_symlink_target_lock); -/** - * sysfs_pathname - return full path to sysfs dirent - * @kn: kernfs_node whose path we want - * @path: caller allocated buffer of size PATH_MAX - * - * Gives the name "/" to the sysfs_root entry; any path returned - * is relative to wherever sysfs is mounted. - */ -static char *sysfs_pathname(struct kernfs_node *kn, char *path) -{ - if (kn->parent) { - sysfs_pathname(kn->parent, path); - strlcat(path, "/", PATH_MAX); - } - strlcat(path, kn->name, PATH_MAX); - return path; -} - void sysfs_warn_dup(struct kernfs_node *parent, const char *name) { - char *path; + char *buf, *path = NULL; - path = kzalloc(PATH_MAX, GFP_KERNEL); - if (path) { - sysfs_pathname(parent, path); - strlcat(path, "/", PATH_MAX); - strlcat(path, name, PATH_MAX); - } + buf = kzalloc(PATH_MAX, GFP_KERNEL); + if (buf) + path = kernfs_path(parent, buf, PATH_MAX); - WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s'\n", - path ? path : name); + WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s/%s'\n", + path, name); - kfree(path); + kfree(buf); } /** @@ -122,9 +101,13 @@ void sysfs_remove_dir(struct kobject *kobj) int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name, const void *new_ns) { - struct kernfs_node *parent = kobj->sd->parent; + struct kernfs_node *parent; + int ret; - return kernfs_rename_ns(kobj->sd, parent, new_name, new_ns); + parent = kernfs_get_parent(kobj->sd); + ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns); + kernfs_put(parent); + return ret; } int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj, @@ -133,7 +116,6 @@ int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj, struct kernfs_node *kn = kobj->sd; struct kernfs_node *new_parent; - BUG_ON(!kn->parent); new_parent = new_parent_kobj && new_parent_kobj->sd ? new_parent_kobj->sd : sysfs_root_kn; diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 810cf6e..28cc1acd 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -372,6 +372,29 @@ void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, } EXPORT_SYMBOL_GPL(sysfs_remove_file_ns); +/** + * sysfs_remove_file_self - remove an object attribute from its own method + * @kobj: object we're acting for + * @attr: attribute descriptor + * + * See kernfs_remove_self() for details. + */ +bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr) +{ + struct kernfs_node *parent = kobj->sd; + struct kernfs_node *kn; + bool ret; + + kn = kernfs_find_and_get(parent, attr->name); + if (WARN_ON_ONCE(!kn)) + return false; + + ret = kernfs_remove_self(kn); + + kernfs_put(kn); + return ret; +} + void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr) { int i; @@ -430,95 +453,3 @@ void sysfs_remove_bin_file(struct kobject *kobj, kernfs_remove_by_name(kobj->sd, attr->attr.name); } EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); - -struct sysfs_schedule_callback_struct { - struct list_head workq_list; - struct kobject *kobj; - void (*func)(void *); - void *data; - struct module *owner; - struct work_struct work; -}; - -static struct workqueue_struct *sysfs_workqueue; -static DEFINE_MUTEX(sysfs_workq_mutex); -static LIST_HEAD(sysfs_workq); -static void sysfs_schedule_callback_work(struct work_struct *work) -{ - struct sysfs_schedule_callback_struct *ss = container_of(work, - struct sysfs_schedule_callback_struct, work); - - (ss->func)(ss->data); - kobject_put(ss->kobj); - module_put(ss->owner); - mutex_lock(&sysfs_workq_mutex); - list_del(&ss->workq_list); - mutex_unlock(&sysfs_workq_mutex); - kfree(ss); -} - -/** - * sysfs_schedule_callback - helper to schedule a callback for a kobject - * @kobj: object we're acting for. - * @func: callback function to invoke later. - * @data: argument to pass to @func. - * @owner: module owning the callback code - * - * sysfs attribute methods must not unregister themselves or their parent - * kobject (which would amount to the same thing). Attempts to do so will - * deadlock, since unregistration is mutually exclusive with driver - * callbacks. - * - * Instead methods can call this routine, which will attempt to allocate - * and schedule a workqueue request to call back @func with @data as its - * argument in the workqueue's process context. @kobj will be pinned - * until @func returns. - * - * Returns 0 if the request was submitted, -ENOMEM if storage could not - * be allocated, -ENODEV if a reference to @owner isn't available, - * -EAGAIN if a callback has already been scheduled for @kobj. - */ -int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), - void *data, struct module *owner) -{ - struct sysfs_schedule_callback_struct *ss, *tmp; - - if (!try_module_get(owner)) - return -ENODEV; - - mutex_lock(&sysfs_workq_mutex); - list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) - if (ss->kobj == kobj) { - module_put(owner); - mutex_unlock(&sysfs_workq_mutex); - return -EAGAIN; - } - mutex_unlock(&sysfs_workq_mutex); - - if (sysfs_workqueue == NULL) { - sysfs_workqueue = create_singlethread_workqueue("sysfsd"); - if (sysfs_workqueue == NULL) { - module_put(owner); - return -ENOMEM; - } - } - - ss = kmalloc(sizeof(*ss), GFP_KERNEL); - if (!ss) { - module_put(owner); - return -ENOMEM; - } - kobject_get(kobj); - ss->kobj = kobj; - ss->func = func; - ss->data = data; - ss->owner = owner; - INIT_WORK(&ss->work, sysfs_schedule_callback_work); - INIT_LIST_HEAD(&ss->workq_list); - mutex_lock(&sysfs_workq_mutex); - list_add_tail(&ss->workq_list, &sysfs_workq); - mutex_unlock(&sysfs_workq_mutex); - queue_work(sysfs_workqueue, &ss->work); - return 0; -} -EXPORT_SYMBOL_GPL(sysfs_schedule_callback); diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 6211230..5c7fdd9 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -62,7 +62,7 @@ int __init sysfs_init(void) { int err; - sysfs_root = kernfs_create_root(NULL, NULL); + sysfs_root = kernfs_create_root(NULL, 0, NULL); if (IS_ERR(sysfs_root)) return PTR_ERR(sysfs_root); diff --git a/include/linux/device.h b/include/linux/device.h index 952b010..fb1ba13 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -560,16 +560,12 @@ extern int device_create_file(struct device *device, const struct device_attribute *entry); extern void device_remove_file(struct device *dev, const struct device_attribute *attr); +extern bool device_remove_file_self(struct device *dev, + const struct device_attribute *attr); extern int __must_check device_create_bin_file(struct device *dev, const struct bin_attribute *attr); extern void device_remove_bin_file(struct device *dev, const struct bin_attribute *attr); -extern int device_schedule_callback_owner(struct device *dev, - void (*func)(struct device *dev), struct module *owner); - -/* This is a macro to avoid include problems with THIS_MODULE */ -#define device_schedule_callback(dev, func) \ - device_schedule_callback_owner(dev, func, THIS_MODULE) /* device resource management */ typedef void (*dr_release_t)(struct device *dev, void *res); @@ -929,10 +925,7 @@ extern int device_online(struct device *dev); extern struct device *__root_device_register(const char *name, struct module *owner); -/* - * This is a macro to avoid include problems with THIS_MODULE, - * just as per what is done for device_schedule_callback() above. - */ +/* This is a macro to avoid include problems with THIS_MODULE */ #define root_device_register(name) \ __root_device_register(name, THIS_MODULE) diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index 5be9f02..649497a 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -15,7 +15,7 @@ #include <linux/lockdep.h> #include <linux/rbtree.h> #include <linux/atomic.h> -#include <linux/completion.h> +#include <linux/wait.h> struct file; struct dentry; @@ -35,16 +35,22 @@ enum kernfs_node_type { }; #define KERNFS_TYPE_MASK 0x000f -#define KERNFS_ACTIVE_REF KERNFS_FILE #define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK enum kernfs_node_flag { - KERNFS_REMOVED = 0x0010, + KERNFS_ACTIVATED = 0x0010, KERNFS_NS = 0x0020, KERNFS_HAS_SEQ_SHOW = 0x0040, KERNFS_HAS_MMAP = 0x0080, KERNFS_LOCKDEP = 0x0100, KERNFS_STATIC_NAME = 0x0200, + KERNFS_SUICIDAL = 0x0400, + KERNFS_SUICIDED = 0x0800, +}; + +/* @flags for kernfs_create_root() */ +enum kernfs_root_flag { + KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001, }; /* type-specific structures for kernfs_node union members */ @@ -85,17 +91,17 @@ struct kernfs_node { #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; #endif - /* the following two fields are published */ + /* + * Use kernfs_get_parent() and kernfs_name/path() instead of + * accessing the following two fields directly. If the node is + * never moved to a different parent, it is safe to access the + * parent directly. + */ struct kernfs_node *parent; const char *name; struct rb_node rb; - union { - struct completion *completion; - struct kernfs_node *removed_list; - } u; - const void *ns; /* namespace tag */ unsigned int hash; /* ns + name hash */ union { @@ -113,12 +119,16 @@ struct kernfs_node { }; /* - * kernfs_dir_ops may be specified on kernfs_create_root() to support - * directory manipulation syscalls. These optional callbacks are invoked - * on the matching syscalls and can perform any kernfs operations which - * don't necessarily have to be the exact operation requested. + * kernfs_syscall_ops may be specified on kernfs_create_root() to support + * syscalls. These optional callbacks are invoked on the matching syscalls + * and can perform any kernfs operations which don't necessarily have to be + * the exact operation requested. An active reference is held for each + * kernfs_node parameter. */ -struct kernfs_dir_ops { +struct kernfs_syscall_ops { + int (*remount_fs)(struct kernfs_root *root, int *flags, char *data); + int (*show_options)(struct seq_file *sf, struct kernfs_root *root); + int (*mkdir)(struct kernfs_node *parent, const char *name, umode_t mode); int (*rmdir)(struct kernfs_node *kn); @@ -129,16 +139,19 @@ struct kernfs_dir_ops { struct kernfs_root { /* published fields */ struct kernfs_node *kn; + unsigned int flags; /* KERNFS_ROOT_* flags */ /* private fields, do not use outside kernfs proper */ struct ida ino_ida; - struct kernfs_dir_ops *dir_ops; + struct kernfs_syscall_ops *syscall_ops; + wait_queue_head_t deactivate_waitq; }; struct kernfs_open_file { /* published fields */ struct kernfs_node *kn; struct file *file; + void *priv; /* private fields, do not use outside kernfs proper */ struct mutex mutex; @@ -171,9 +184,13 @@ struct kernfs_ops { loff_t off); /* - * write() is bounced through kernel buffer and a write larger than - * PAGE_SIZE results in partial operation of PAGE_SIZE. + * write() is bounced through kernel buffer. If atomic_write_len + * is not set, a write larger than PAGE_SIZE results in partial + * operations of PAGE_SIZE chunks. If atomic_write_len is set, + * writes upto the specified size are executed atomically but + * larger ones are rejected with -E2BIG. */ + size_t atomic_write_len; ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes, loff_t off); @@ -184,7 +201,7 @@ struct kernfs_ops { #endif }; -#ifdef CONFIG_SYSFS +#ifdef CONFIG_KERNFS static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) { @@ -217,13 +234,22 @@ static inline bool kernfs_ns_enabled(struct kernfs_node *kn) return kn->flags & KERNFS_NS; } +int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen); +char * __must_check kernfs_path(struct kernfs_node *kn, char *buf, + size_t buflen); +void pr_cont_kernfs_name(struct kernfs_node *kn); +void pr_cont_kernfs_path(struct kernfs_node *kn); +struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn); struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, const void *ns); void kernfs_get(struct kernfs_node *kn); void kernfs_put(struct kernfs_node *kn); -struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, - void *priv); +struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry); +struct kernfs_root *kernfs_root_from_sb(struct super_block *sb); + +struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, + unsigned int flags, void *priv); void kernfs_destroy_root(struct kernfs_root *root); struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, @@ -239,7 +265,11 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, const char *name, struct kernfs_node *target); +void kernfs_activate(struct kernfs_node *kn); void kernfs_remove(struct kernfs_node *kn); +void kernfs_break_active_protection(struct kernfs_node *kn); +void kernfs_unbreak_active_protection(struct kernfs_node *kn); +bool kernfs_remove_self(struct kernfs_node *kn); int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, const void *ns); int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, @@ -254,7 +284,7 @@ void kernfs_kill_sb(struct super_block *sb); void kernfs_init(void); -#else /* CONFIG_SYSFS */ +#else /* CONFIG_KERNFS */ static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) { return 0; } /* whatever */ @@ -264,6 +294,19 @@ static inline void kernfs_enable_ns(struct kernfs_node *kn) { } static inline bool kernfs_ns_enabled(struct kernfs_node *kn) { return false; } +static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) +{ return -ENOSYS; } + +static inline char * __must_check kernfs_path(struct kernfs_node *kn, char *buf, + size_t buflen) +{ return NULL; } + +static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { } +static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { } + +static inline struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) +{ return NULL; } + static inline struct kernfs_node * kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, const void *ns) @@ -272,8 +315,15 @@ kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, static inline void kernfs_get(struct kernfs_node *kn) { } static inline void kernfs_put(struct kernfs_node *kn) { } +static inline struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) +{ return NULL; } + +static inline struct kernfs_root *kernfs_root_from_sb(struct super_block *sb) +{ return NULL; } + static inline struct kernfs_root * -kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv) +kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags, + void *priv) { return ERR_PTR(-ENOSYS); } static inline void kernfs_destroy_root(struct kernfs_root *root) { } @@ -295,8 +345,13 @@ kernfs_create_link(struct kernfs_node *parent, const char *name, struct kernfs_node *target) { return ERR_PTR(-ENOSYS); } +static inline void kernfs_activate(struct kernfs_node *kn) { } + static inline void kernfs_remove(struct kernfs_node *kn) { } +static inline bool kernfs_remove_self(struct kernfs_node *kn) +{ return false; } + static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn, const char *name, const void *ns) { return -ENOSYS; } @@ -324,7 +379,7 @@ static inline void kernfs_kill_sb(struct super_block *sb) { } static inline void kernfs_init(void) { } -#endif /* CONFIG_SYSFS */ +#endif /* CONFIG_KERNFS */ static inline struct kernfs_node * kernfs_find_and_get(struct kernfs_node *kn, const char *name) @@ -366,6 +421,13 @@ static inline int kernfs_remove_by_name(struct kernfs_node *parent, return kernfs_remove_by_name_ns(parent, name, NULL); } +static inline int kernfs_rename(struct kernfs_node *kn, + struct kernfs_node *new_parent, + const char *new_name) +{ + return kernfs_rename_ns(kn, new_parent, new_name, NULL); +} + static inline struct dentry * kernfs_mount(struct file_system_type *fs_type, int flags, struct kernfs_root *root) diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 30b2ebe..fdaa0c6 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -178,9 +178,6 @@ struct sysfs_ops { #ifdef CONFIG_SYSFS -int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), - void *data, struct module *owner); - int __must_check sysfs_create_dir_ns(struct kobject *kobj, const void *ns); void sysfs_remove_dir(struct kobject *kobj); int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name, @@ -198,6 +195,7 @@ int __must_check sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, umode_t mode); void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, const void *ns); +bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr); void sysfs_remove_files(struct kobject *kobj, const struct attribute **attr); int __must_check sysfs_create_bin_file(struct kobject *kobj, @@ -246,14 +244,13 @@ void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr); int __must_check sysfs_init(void); -#else /* CONFIG_SYSFS */ - -static inline int sysfs_schedule_callback(struct kobject *kobj, - void (*func)(void *), void *data, struct module *owner) +static inline void sysfs_enable_ns(struct kernfs_node *kn) { - return -ENOSYS; + return kernfs_enable_ns(kn); } +#else /* CONFIG_SYSFS */ + static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns) { return 0; @@ -301,6 +298,12 @@ static inline void sysfs_remove_file_ns(struct kobject *kobj, { } +static inline bool sysfs_remove_file_self(struct kobject *kobj, + const struct attribute *attr) +{ + return false; +} + static inline void sysfs_remove_files(struct kobject *kobj, const struct attribute **attr) { @@ -418,6 +421,10 @@ static inline int __must_check sysfs_init(void) return 0; } +static inline void sysfs_enable_ns(struct kernfs_node *kn) +{ +} + #endif /* CONFIG_SYSFS */ static inline int __must_check sysfs_create_file(struct kobject *kobj, diff --git a/lib/kobject.c b/lib/kobject.c index cb14aea..58751bb 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -94,7 +94,7 @@ static int create_dir(struct kobject *kobj) BUG_ON(ops->type >= KOBJ_NS_TYPES); BUG_ON(!kobj_ns_type_registered(ops->type)); - kernfs_enable_ns(kobj->sd); + sysfs_enable_ns(kobj->sd); } return 0; |
