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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-13 14:05:13 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-13 14:05:13 -0800
commita9f138b0e537de55933335d580ebd38c2bc53c47 (patch)
treef54235f920d392519bde975d42aa4b4534f9561a
parent8634c422c1b7e50ca8e346f65afc140d93a3212c (diff)
downloadop-kernel-dev-a9f138b0e537de55933335d580ebd38c2bc53c47.zip
op-kernel-dev-a9f138b0e537de55933335d580ebd38c2bc53c47.tar.gz
Revert "kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers"
This reverts commit 1ae06819c77cff1ea2833c94f8c093fe8a5c79db. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/base/core.c17
-rw-r--r--fs/kernfs/dir.c72
-rw-r--r--fs/sysfs/file.c23
-rw-r--r--include/linux/device.h2
-rw-r--r--include/linux/kernfs.h6
-rw-r--r--include/linux/sysfs.h7
6 files changed, 0 insertions, 127 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 9db57af..2b56717 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -571,23 +571,6 @@ 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.
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index a8028be..1aeb579 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -986,78 +986,6 @@ void kernfs_remove(struct kernfs_node *kn)
}
/**
- * 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_deactivate_self(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;
- }
-
- __kernfs_reactivate_self(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
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 1b8b91b..810cf6e 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -372,29 +372,6 @@ 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;
diff --git a/include/linux/device.h b/include/linux/device.h
index 1ff3f16..952b010 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -560,8 +560,6 @@ 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,
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 0b7b7cc..ac86930 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -43,8 +43,6 @@ enum kernfs_node_flag {
KERNFS_HAS_MMAP = 0x0080,
KERNFS_LOCKDEP = 0x0100,
KERNFS_STATIC_NAME = 0x0200,
- KERNFS_SUICIDAL = 0x0400,
- KERNFS_SUICIDED = 0x0800,
};
/* type-specific structures for kernfs_node union members */
@@ -241,7 +239,6 @@ void kernfs_reactivate(struct kernfs_node *kn);
void kernfs_deactivate_self(struct kernfs_node *kn);
void kernfs_reactivate_self(struct kernfs_node *kn);
void kernfs_remove(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,
@@ -299,9 +296,6 @@ kernfs_create_link(struct kernfs_node *parent, const char *name,
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; }
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index bd96c60..30b2ebe 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -198,7 +198,6 @@ 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,
@@ -302,12 +301,6 @@ 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)
{
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