diff options
Diffstat (limited to 'block/genhd.c')
| -rw-r--r-- | block/genhd.c | 1196 |
1 files changed, 1196 insertions, 0 deletions
diff --git a/block/genhd.c b/block/genhd.c new file mode 100644 index 0000000..2f7feda --- /dev/null +++ b/block/genhd.c @@ -0,0 +1,1196 @@ +/* + * gendisk handling + */ + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/genhd.h> +#include <linux/kdev_t.h> +#include <linux/kernel.h> +#include <linux/blkdev.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <linux/kmod.h> +#include <linux/kobj_map.h> +#include <linux/buffer_head.h> +#include <linux/mutex.h> +#include <linux/idr.h> + +#include "blk.h" + +static DEFINE_MUTEX(block_class_lock); +#ifndef CONFIG_SYSFS_DEPRECATED +struct kobject *block_depr; +#endif + +/* for extended dynamic devt allocation, currently only one major is used */ +#define MAX_EXT_DEVT (1 << MINORBITS) + +/* For extended devt allocation. ext_devt_mutex prevents look up + * results from going away underneath its user. + */ +static DEFINE_MUTEX(ext_devt_mutex); +static DEFINE_IDR(ext_devt_idr); + +static struct device_type disk_type; + +/** + * disk_get_part - get partition + * @disk: disk to look partition from + * @partno: partition number + * + * Look for partition @partno from @disk. If found, increment + * reference count and return it. + * + * CONTEXT: + * Don't care. + * + * RETURNS: + * Pointer to the found partition on success, NULL if not found. + */ +struct hd_struct *disk_get_part(struct gendisk *disk, int partno) +{ + struct hd_struct *part = NULL; + struct disk_part_tbl *ptbl; + + if (unlikely(partno < 0)) + return NULL; + + rcu_read_lock(); + + ptbl = rcu_dereference(disk->part_tbl); + if (likely(partno < ptbl->len)) { + part = rcu_dereference(ptbl->part[partno]); + if (part) + get_device(part_to_dev(part)); + } + + rcu_read_unlock(); + + return part; +} +EXPORT_SYMBOL_GPL(disk_get_part); + +/** + * disk_part_iter_init - initialize partition iterator + * @piter: iterator to initialize + * @disk: disk to iterate over + * @flags: DISK_PITER_* flags + * + * Initialize @piter so that it iterates over partitions of @disk. + * + * CONTEXT: + * Don't care. + */ +void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, + unsigned int flags) +{ + struct disk_part_tbl *ptbl; + + rcu_read_lock(); + ptbl = rcu_dereference(disk->part_tbl); + + piter->disk = disk; + piter->part = NULL; + + if (flags & DISK_PITER_REVERSE) + piter->idx = ptbl->len - 1; + else if (flags & DISK_PITER_INCL_PART0) + piter->idx = 0; + else + piter->idx = 1; + + piter->flags = flags; + + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(disk_part_iter_init); + +/** + * disk_part_iter_next - proceed iterator to the next partition and return it + * @piter: iterator of interest + * + * Proceed @piter to the next partition and return it. + * + * CONTEXT: + * Don't care. + */ +struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) +{ + struct disk_part_tbl *ptbl; + int inc, end; + + /* put the last partition */ + disk_put_part(piter->part); + piter->part = NULL; + + /* get part_tbl */ + rcu_read_lock(); + ptbl = rcu_dereference(piter->disk->part_tbl); + + /* determine iteration parameters */ + if (piter->flags & DISK_PITER_REVERSE) { + inc = -1; + if (piter->flags & DISK_PITER_INCL_PART0) + end = -1; + else + end = 0; + } else { + inc = 1; + end = ptbl->len; + } + + /* iterate to the next partition */ + for (; piter->idx != end; piter->idx += inc) { + struct hd_struct *part; + + part = rcu_dereference(ptbl->part[piter->idx]); + if (!part) + continue; + if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects) + continue; + + get_device(part_to_dev(part)); + piter->part = part; + piter->idx += inc; + break; + } + + rcu_read_unlock(); + + return piter->part; +} +EXPORT_SYMBOL_GPL(disk_part_iter_next); + +/** + * disk_part_iter_exit - finish up partition iteration + * @piter: iter of interest + * + * Called when iteration is over. Cleans up @piter. + * + * CONTEXT: + * Don't care. + */ +void disk_part_iter_exit(struct disk_part_iter *piter) +{ + disk_put_part(piter->part); + piter->part = NULL; +} +EXPORT_SYMBOL_GPL(disk_part_iter_exit); + +/** + * disk_map_sector_rcu - map sector to partition + * @disk: gendisk of interest + * @sector: sector to map + * + * Find out which partition @sector maps to on @disk. This is + * primarily used for stats accounting. + * + * CONTEXT: + * RCU read locked. The returned partition pointer is valid only + * while preemption is disabled. + * + * RETURNS: + * Found partition on success, part0 is returned if no partition matches + */ +struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector) +{ + struct disk_part_tbl *ptbl; + int i; + + ptbl = rcu_dereference(disk->part_tbl); + + for (i = 1; i < ptbl->len; i++) { + struct hd_struct *part = rcu_dereference(ptbl->part[i]); + + if (part && part->start_sect <= sector && + sector < part->start_sect + part->nr_sects) + return part; + } + return &disk->part0; +} +EXPORT_SYMBOL_GPL(disk_map_sector_rcu); + +/* + * Can be deleted altogether. Later. + * + */ +static struct blk_major_name { + struct blk_major_name *next; + int major; + char name[16]; +} *major_names[BLKDEV_MAJOR_HASH_SIZE]; + +/* index in the above - for now: assume no multimajor ranges */ +static inline int major_to_index(int major) +{ + return major % BLKDEV_MAJOR_HASH_SIZE; +} + +#ifdef CONFIG_PROC_FS +void blkdev_show(struct seq_file *seqf, off_t offset) +{ + struct blk_major_name *dp; + + if (offset < BLKDEV_MAJOR_HASH_SIZE) { + mutex_lock(&block_class_lock); + for (dp = major_names[offset]; dp; dp = dp->next) + seq_printf(seqf, "%3d %s\n", dp->major, dp->name); + mutex_unlock(&block_class_lock); + } +} +#endif /* CONFIG_PROC_FS */ + +int register_blkdev(unsigned int major, const char *name) +{ + struct blk_major_name **n, *p; + int index, ret = 0; + + mutex_lock(&block_class_lock); + + /* temporary */ + if (major == 0) { + for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) { + if (major_names[index] == NULL) + break; + } + + if (index == 0) { + printk("register_blkdev: failed to get major for %s\n", + name); + ret = -EBUSY; + goto out; + } + major = index; + ret = major; + } + + p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL); + if (p == NULL) { + ret = -ENOMEM; + goto out; + } + + p->major = major; + strlcpy(p->name, name, sizeof(p->name)); + p->next = NULL; + index = major_to_index(major); + + for (n = &major_names[index]; *n; n = &(*n)->next) { + if ((*n)->major == major) + break; + } + if (!*n) + *n = p; + else + ret = -EBUSY; + + if (ret < 0) { + printk("register_blkdev: cannot get major %d for %s\n", + major, name); + kfree(p); + } +out: + mutex_unlock(&block_class_lock); + return ret; +} + +EXPORT_SYMBOL(register_blkdev); + +void unregister_blkdev(unsigned int major, const char *name) +{ + struct blk_major_name **n; + struct blk_major_name *p = NULL; + int index = major_to_index(major); + + mutex_lock(&block_class_lock); + for (n = &major_names[index]; *n; n = &(*n)->next) + if ((*n)->major == major) + break; + if (!*n || strcmp((*n)->name, name)) { + WARN_ON(1); + } else { + p = *n; + *n = p->next; + } + mutex_unlock(&block_class_lock); + kfree(p); +} + +EXPORT_SYMBOL(unregister_blkdev); + +static struct kobj_map *bdev_map; + +/** + * blk_mangle_minor - scatter minor numbers apart + * @minor: minor number to mangle + * + * Scatter consecutively allocated @minor number apart if MANGLE_DEVT + * is enabled. Mangling twice gives the original value. + * + * RETURNS: + * Mangled value. + * + * CONTEXT: + * Don't care. + */ +static int blk_mangle_minor(int minor) +{ +#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT + int i; + + for (i = 0; i < MINORBITS / 2; i++) { + int low = minor & (1 << i); + int high = minor & (1 << (MINORBITS - 1 - i)); + int distance = MINORBITS - 1 - 2 * i; + + minor ^= low | high; /* clear both bits */ + low <<= distance; /* swap the positions */ + high >>= distance; + minor |= low | high; /* and set */ + } +#endif + return minor; +} + +/** + * blk_alloc_devt - allocate a dev_t for a partition + * @part: partition to allocate dev_t for + * @devt: out parameter for resulting dev_t + * + * Allocate a dev_t for block device. + * + * RETURNS: + * 0 on success, allocated dev_t is returned in *@devt. -errno on + * failure. + * + * CONTEXT: + * Might sleep. + */ +int blk_alloc_devt(struct hd_struct *part, dev_t *devt) +{ + struct gendisk *disk = part_to_disk(part); + int idx, rc; + + /* in consecutive minor range? */ + if (part->partno < disk->minors) { + *devt = MKDEV(disk->major, disk->first_minor + part->partno); + return 0; + } + + /* allocate ext devt */ + do { + if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL)) + return -ENOMEM; + rc = idr_get_new(&ext_devt_idr, part, &idx); + } while (rc == -EAGAIN); + + if (rc) + return rc; + + if (idx > MAX_EXT_DEVT) { + idr_remove(&ext_devt_idr, idx); + return -EBUSY; + } + + *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx)); + return 0; +} + +/** + * blk_free_devt - free a dev_t + * @devt: dev_t to free + * + * Free @devt which was allocated using blk_alloc_devt(). + * + * CONTEXT: + * Might sleep. + */ +void blk_free_devt(dev_t devt) +{ + might_sleep(); + + if (devt == MKDEV(0, 0)) + return; + + if (MAJOR(devt) == BLOCK_EXT_MAJOR) { + mutex_lock(&ext_devt_mutex); + idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); + mutex_unlock(&ext_devt_mutex); + } +} + +static char *bdevt_str(dev_t devt, char *buf) +{ + if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) { + char tbuf[BDEVT_SIZE]; + snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt)); + snprintf(buf, BDEVT_SIZE, "%-9s", tbuf); + } else + snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt)); + + return buf; +} + +/* + * Register device numbers dev..(dev+range-1) + * range must be nonzero + * The hash chain is sorted on range, so that subranges can override. + */ +void blk_register_region(dev_t devt, unsigned long range, struct module *module, + struct kobject *(*probe)(dev_t, int *, void *), + int (*lock)(dev_t, void *), void *data) +{ + kobj_map(bdev_map, devt, range, module, probe, lock, data); +} + +EXPORT_SYMBOL(blk_register_region); + +void blk_unregister_region(dev_t devt, unsigned long range) +{ + kobj_unmap(bdev_map, devt, range); +} + +EXPORT_SYMBOL(blk_unregister_region); + +static struct kobject *exact_match(dev_t devt, int *partno, void *data) +{ + struct gendisk *p = data; + + return &disk_to_dev(p)->kobj; +} + +static int exact_lock(dev_t devt, void *data) +{ + struct gendisk *p = data; + + if (!get_disk(p)) + return -1; + return 0; +} + +/** + * add_disk - add partitioning information to kernel list + * @disk: per-device partitioning information + * + * This function registers the partitioning information in @disk + * with the kernel. + * + * FIXME: error handling + */ +void add_disk(struct gendisk *disk) +{ + struct backing_dev_info *bdi; + dev_t devt; + int retval; + + /* minors == 0 indicates to use ext devt from part0 and should + * be accompanied with EXT_DEVT flag. Make sure all + * parameters make sense. + */ + WARN_ON(disk->minors && !(disk->major || disk->first_minor)); + WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT)); + + disk->flags |= GENHD_FL_UP; + + retval = blk_alloc_devt(&disk->part0, &devt); + if (retval) { + WARN_ON(1); + return; + } + disk_to_dev(disk)->devt = devt; + + /* ->major and ->first_minor aren't supposed to be + * dereferenced from here on, but set them just in case. + */ + disk->major = MAJOR(devt); + disk->first_minor = MINOR(devt); + + blk_register_region(disk_devt(disk), disk->minors, NULL, + exact_match, exact_lock, disk); + register_disk(disk); + blk_register_queue(disk); + + bdi = &disk->queue->backing_dev_info; + bdi_register_dev(bdi, disk_devt(disk)); + retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj, + "bdi"); + WARN_ON(retval); +} + +EXPORT_SYMBOL(add_disk); +EXPORT_SYMBOL(del_gendisk); /* in partitions/check.c */ + +void unlink_gendisk(struct gendisk *disk) +{ + sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); + bdi_unregister(&disk->queue->backing_dev_info); + blk_unregister_queue(disk); + blk_unregister_region(disk_devt(disk), disk->minors); +} + +/** + * get_gendisk - get partitioning information for a given device + * @devt: device to get partitioning information for + * @partno: returned partition index + * + * This function gets the structure containing partitioning + * information for the given device @devt. + */ +struct gendisk *get_gendisk(dev_t devt, int *partno) +{ + struct gendisk *disk = NULL; + + if (MAJOR(devt) != BLOCK_EXT_MAJOR) { + struct kobject *kobj; + + kobj = kobj_lookup(bdev_map, devt, partno); + if (kobj) + disk = dev_to_disk(kobj_to_dev(kobj)); + } else { + struct hd_struct *part; + + mutex_lock(&ext_devt_mutex); + part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); + if (part && get_disk(part_to_disk(part))) { + *partno = part->partno; + disk = part_to_disk(part); + } + mutex_unlock(&ext_devt_mutex); + } + + return disk; +} + +/** + * bdget_disk - do bdget() by gendisk and partition number + * @disk: gendisk of interest + * @partno: partition number + * + * Find partition @partno from @disk, do bdget() on it. + * + * CONTEXT: + * Don't care. + * + * RETURNS: + * Resulting block_device on success, NULL on failure. + */ +struct block_device *bdget_disk(struct gendisk *disk, int partno) +{ + struct hd_struct *part; + struct block_device *bdev = NULL; + + part = disk_get_part(disk, partno); + if (part) + bdev = bdget(part_devt(part)); + disk_put_part(part); + + return bdev; +} +EXPORT_SYMBOL(bdget_disk); + +/* + * print a full list of all partitions - intended for places where the root + * filesystem can't be mounted and thus to give the victim some idea of what + * went wrong + */ +void __init printk_all_partitions(void) +{ + struct class_dev_iter iter; + struct device *dev; + + class_dev_iter_init(&iter, &block_class, NULL, &disk_type); + while ((dev = class_dev_iter_next(&iter))) { + struct gendisk *disk = dev_to_disk(dev); + struct disk_part_iter piter; + struct hd_struct *part; + char name_buf[BDEVNAME_SIZE]; + char devt_buf[BDEVT_SIZE]; + + /* + * Don't show empty devices or things that have been + * surpressed + */ + if (get_capacity(disk) == 0 || + (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)) + continue; + + /* + * Note, unlike /proc/partitions, I am showing the + * numbers in hex - the same format as the root= + * option takes. + */ + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0); + while ((part = disk_part_iter_next(&piter))) { + bool is_part0 = part == &disk->part0; + + printk("%s%s %10llu %s", is_part0 ? "" : " ", + bdevt_str(part_devt(part), devt_buf), + (unsigned long long)part->nr_sects >> 1, + disk_name(disk, part->partno, name_buf)); + if (is_part0) { + if (disk->driverfs_dev != NULL && + disk->driverfs_dev->driver != NULL) + printk(" driver: %s\n", + disk->driverfs_dev->driver->name); + else + printk(" (driver?)\n"); + } else + printk("\n"); + } + disk_part_iter_exit(&piter); + } + class_dev_iter_exit(&iter); +} + +#ifdef CONFIG_PROC_FS +/* iterator */ +static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos) +{ + loff_t skip = *pos; + struct class_dev_iter *iter; + struct device *dev; + + iter = kmalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) + return ERR_PTR(-ENOMEM); + + seqf->private = iter; + class_dev_iter_init(iter, &block_class, NULL, &disk_type); + do { + dev = class_dev_iter_next(iter); + if (!dev) + return NULL; + } while (skip--); + + return dev_to_disk(dev); +} + +static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos) +{ + struct device *dev; + + (*pos)++; + dev = class_dev_iter_next(seqf->private); + if (dev) + return dev_to_disk(dev); + + return NULL; +} + +static void disk_seqf_stop(struct seq_file *seqf, void *v) +{ + struct class_dev_iter *iter = seqf->private; + + /* stop is called even after start failed :-( */ + if (iter) { + class_dev_iter_exit(iter); + kfree(iter); + } +} + +static void *show_partition_start(struct seq_file *seqf, loff_t *pos) +{ + static void *p; + + p = disk_seqf_start(seqf, pos); + if (!IS_ERR(p) && p && !*pos) + seq_puts(seqf, "major minor #blocks name\n\n"); + return p; +} + +static int show_partition(struct seq_file *seqf, void *v) +{ + struct gendisk *sgp = v; + struct disk_part_iter piter; + struct hd_struct *part; + char buf[BDEVNAME_SIZE]; + + /* Don't show non-partitionable removeable devices or empty devices */ + if (!get_capacity(sgp) || (!disk_partitionable(sgp) && + (sgp->flags & GENHD_FL_REMOVABLE))) + return 0; + if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO) + return 0; + + /* show the full disk and all non-0 size partitions of it */ + disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0); + while ((part = disk_part_iter_next(&piter))) + seq_printf(seqf, "%4d %7d %10llu %s\n", + MAJOR(part_devt(part)), MINOR(part_devt(part)), + (unsigned long long)part->nr_sects >> 1, + disk_name(sgp, part->partno, buf)); + disk_part_iter_exit(&piter); + + return 0; +} + +static const struct seq_operations partitions_op = { + .start = show_partition_start, + .next = disk_seqf_next, + .stop = disk_seqf_stop, + .show = show_partition +}; + +static int partitions_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &partitions_op); +} + +static const struct file_operations proc_partitions_operations = { + .open = partitions_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; +#endif + + +static struct kobject *base_probe(dev_t devt, int *partno, void *data) +{ + if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0) + /* Make old-style 2.4 aliases work */ + request_module("block-major-%d", MAJOR(devt)); + return NULL; +} + +static int __init genhd_device_init(void) +{ + int error; + + block_class.dev_kobj = sysfs_dev_block_kobj; + error = class_register(&block_class); + if (unlikely(error)) + return error; + bdev_map = kobj_map_init(base_probe, &block_class_lock); + blk_dev_init(); + + register_blkdev(BLOCK_EXT_MAJOR, "blkext"); + +#ifndef CONFIG_SYSFS_DEPRECATED + /* create top-level block dir */ + block_depr = kobject_create_and_add("block", NULL); +#endif + return 0; +} + +subsys_initcall(genhd_device_init); + +static ssize_t disk_range_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", disk->minors); +} + +static ssize_t disk_ext_range_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", disk_max_parts(disk)); +} + +static ssize_t disk_removable_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", + (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0)); +} + +static ssize_t disk_ro_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0); +} + +static ssize_t disk_capability_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%x\n", disk->flags); +} + +static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL); +static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL); +static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL); +static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL); +static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL); +static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL); +static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL); +#ifdef CONFIG_FAIL_MAKE_REQUEST +static struct device_attribute dev_attr_fail = + __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store); +#endif +#ifdef CONFIG_FAIL_IO_TIMEOUT +static struct device_attribute dev_attr_fail_timeout = + __ATTR(io-timeout-fail, S_IRUGO|S_IWUSR, part_timeout_show, + part_timeout_store); +#endif + +static struct attribute *disk_attrs[] = { + &dev_attr_range.attr, + &dev_attr_ext_range.attr, + &dev_attr_removable.attr, + &dev_attr_ro.attr, + &dev_attr_size.attr, + &dev_attr_capability.attr, + &dev_attr_stat.attr, +#ifdef CONFIG_FAIL_MAKE_REQUEST + &dev_attr_fail.attr, +#endif +#ifdef CONFIG_FAIL_IO_TIMEOUT + &dev_attr_fail_timeout.attr, +#endif + NULL +}; + +static struct attribute_group disk_attr_group = { + .attrs = disk_attrs, +}; + +static struct attribute_group *disk_attr_groups[] = { + &disk_attr_group, + NULL +}; + +static void disk_free_ptbl_rcu_cb(struct rcu_head *head) +{ + struct disk_part_tbl *ptbl = + container_of(head, struct disk_part_tbl, rcu_head); + + kfree(ptbl); +} + +/** + * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way + * @disk: disk to replace part_tbl for + * @new_ptbl: new part_tbl to install + * + * Replace disk->part_tbl with @new_ptbl in RCU-safe way. The + * original ptbl is freed using RCU callback. + * + * LOCKING: + * Matching bd_mutx locked. + */ +static void disk_replace_part_tbl(struct gendisk *disk, + struct disk_part_tbl *new_ptbl) +{ + struct disk_part_tbl *old_ptbl = disk->part_tbl; + + rcu_assign_pointer(disk->part_tbl, new_ptbl); + if (old_ptbl) + call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb); +} + +/** + * disk_expand_part_tbl - expand disk->part_tbl + * @disk: disk to expand part_tbl for + * @partno: expand such that this partno can fit in + * + * Expand disk->part_tbl such that @partno can fit in. disk->part_tbl + * uses RCU to allow unlocked dereferencing for stats and other stuff. + * + * LOCKING: + * Matching bd_mutex locked, might sleep. + * + * RETURNS: + * 0 on success, -errno on failure. + */ +int disk_expand_part_tbl(struct gendisk *disk, int partno) +{ + struct disk_part_tbl *old_ptbl = disk->part_tbl; + struct disk_part_tbl *new_ptbl; + int len = old_ptbl ? old_ptbl->len : 0; + int target = partno + 1; + size_t size; + int i; + + /* disk_max_parts() is zero during initialization, ignore if so */ + if (disk_max_parts(disk) && target > disk_max_parts(disk)) + return -EINVAL; + + if (target <= len) + return 0; + + size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]); + new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id); + if (!new_ptbl) + return -ENOMEM; + + INIT_RCU_HEAD(&new_ptbl->rcu_head); + new_ptbl->len = target; + + for (i = 0; i < len; i++) + rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]); + + disk_replace_part_tbl(disk, new_ptbl); + return 0; +} + +static void disk_release(struct device *dev) +{ + struct gendisk *disk = dev_to_disk(dev); + + kfree(disk->random); + disk_replace_part_tbl(disk, NULL); + free_part_stats(&disk->part0); + kfree(disk); +} +struct class block_class = { + .name = "block", +}; + +static struct device_type disk_type = { + .name = "disk", + .groups = disk_attr_groups, + .release = disk_release, +}; + +#ifdef CONFIG_PROC_FS +/* + * aggregate disk stat collector. Uses the same stats that the sysfs + * entries do, above, but makes them available through one seq_file. + * + * The output looks suspiciously like /proc/partitions with a bunch of + * extra fields. + */ +static int diskstats_show(struct seq_file *seqf, void *v) +{ + struct gendisk *gp = v; + struct disk_part_iter piter; + struct hd_struct *hd; + char buf[BDEVNAME_SIZE]; + int cpu; + + /* + if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next) + seq_puts(seqf, "major minor name" + " rio rmerge rsect ruse wio wmerge " + "wsect wuse running use aveq" + "\n\n"); + */ + + disk_part_iter_init(&piter, gp, DISK_PITER_INCL_PART0); + while ((hd = disk_part_iter_next(&piter))) { + cpu = part_stat_lock(); + part_round_stats(cpu, hd); + part_stat_unlock(); + seq_printf(seqf, "%4d %7d %s %lu %lu %llu " + "%u %lu %lu %llu %u %u %u %u\n", + MAJOR(part_devt(hd)), MINOR(part_devt(hd)), + disk_name(gp, hd->partno, buf), + part_stat_read(hd, ios[0]), + part_stat_read(hd, merges[0]), + (unsigned long long)part_stat_read(hd, sectors[0]), + jiffies_to_msecs(part_stat_read(hd, ticks[0])), + part_stat_read(hd, ios[1]), + part_stat_read(hd, merges[1]), + (unsigned long long)part_stat_read(hd, sectors[1]), + jiffies_to_msecs(part_stat_read(hd, ticks[1])), + hd->in_flight, + jiffies_to_msecs(part_stat_read(hd, io_ticks)), + jiffies_to_msecs(part_stat_read(hd, time_in_queue)) + ); + } + disk_part_iter_exit(&piter); + + return 0; +} + +static const struct seq_operations diskstats_op = { + .start = disk_seqf_start, + .next = disk_seqf_next, + .stop = disk_seqf_stop, + .show = diskstats_show +}; + +static int diskstats_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &diskstats_op); +} + +static const struct file_operations proc_diskstats_operations = { + .open = diskstats_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static int __init proc_genhd_init(void) +{ + proc_create("diskstats", 0, NULL, &proc_diskstats_operations); + proc_create("partitions", 0, NULL, &proc_partitions_operations); + return 0; +} +module_init(proc_genhd_init); +#endif /* CONFIG_PROC_FS */ + +static void media_change_notify_thread(struct work_struct *work) +{ + struct gendisk *gd = container_of(work, struct gendisk, async_notify); + char event[] = "MEDIA_CHANGE=1"; + char *envp[] = { event, NULL }; + + /* + * set enviroment vars to indicate which event this is for + * so that user space will know to go check the media status. + */ + kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); + put_device(gd->driverfs_dev); +} + +#if 0 +void genhd_media_change_notify(struct gendisk *disk) +{ + get_device(disk->driverfs_dev); + schedule_work(&disk->async_notify); +} +EXPORT_SYMBOL_GPL(genhd_media_change_notify); +#endif /* 0 */ + +dev_t blk_lookup_devt(const char *name, int partno) +{ + dev_t devt = MKDEV(0, 0); + struct class_dev_iter iter; + struct device *dev; + + class_dev_iter_init(&iter, &block_class, NULL, &disk_type); + while ((dev = class_dev_iter_next(&iter))) { + struct gendisk *disk = dev_to_disk(dev); + struct hd_struct *part; + + if (strcmp(dev->bus_id, name)) + continue; + + part = disk_get_part(disk, partno); + if (part) { + devt = part_devt(part); + disk_put_part(part); + break; + } + disk_put_part(part); + } + class_dev_iter_exit(&iter); + return devt; +} +EXPORT_SYMBOL(blk_lookup_devt); + +struct gendisk *alloc_disk(int minors) +{ + return alloc_disk_node(minors, -1); +} +EXPORT_SYMBOL(alloc_disk); + +struct gendisk *alloc_disk_node(int minors, int node_id) +{ + struct gendisk *disk; + + disk = kmalloc_node(sizeof(struct gendisk), + GFP_KERNEL | __GFP_ZERO, node_id); + if (disk) { + if (!init_part_stats(&disk->part0)) { + kfree(disk); + return NULL; + } + disk->node_id = node_id; + if (disk_expand_part_tbl(disk, 0)) { + free_part_stats(&disk->part0); + kfree(disk); + return NULL; + } + disk->part_tbl->part[0] = &disk->part0; + + disk->minors = minors; + rand_initialize_disk(disk); + disk_to_dev(disk)->class = &block_class; + disk_to_dev(disk)->type = &disk_type; + device_initialize(disk_to_dev(disk)); + INIT_WORK(&disk->async_notify, + media_change_notify_thread); + } + return disk; +} +EXPORT_SYMBOL(alloc_disk_node); + +struct kobject *get_disk(struct gendisk *disk) +{ + struct module *owner; + struct kobject *kobj; + + if (!disk->fops) + return NULL; + owner = disk->fops->owner; + if (owner && !try_module_get(owner)) + return NULL; + kobj = kobject_get(&disk_to_dev(disk)->kobj); + if (kobj == NULL) { + module_put(owner); + return NULL; + } + return kobj; + +} + +EXPORT_SYMBOL(get_disk); + +void put_disk(struct gendisk *disk) +{ + if (disk) + kobject_put(&disk_to_dev(disk)->kobj); +} + +EXPORT_SYMBOL(put_disk); + +void set_device_ro(struct block_device *bdev, int flag) +{ + bdev->bd_part->policy = flag; +} + +EXPORT_SYMBOL(set_device_ro); + +void set_disk_ro(struct gendisk *disk, int flag) +{ + struct disk_part_iter piter; + struct hd_struct *part; + + disk_part_iter_init(&piter, disk, + DISK_PITER_INCL_EMPTY | DISK_PITER_INCL_PART0); + while ((part = disk_part_iter_next(&piter))) + part->policy = flag; + disk_part_iter_exit(&piter); +} + +EXPORT_SYMBOL(set_disk_ro); + +int bdev_read_only(struct block_device *bdev) +{ + if (!bdev) + return 0; + return bdev->bd_part->policy; +} + +EXPORT_SYMBOL(bdev_read_only); + +int invalidate_partition(struct gendisk *disk, int partno) +{ + int res = 0; + struct block_device *bdev = bdget_disk(disk, partno); + if (bdev) { + fsync_bdev(bdev); + res = __invalidate_device(bdev); + bdput(bdev); + } + return res; +} + +EXPORT_SYMBOL(invalidate_partition); 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