diff options
Diffstat (limited to 'block/genhd.c')
| -rw-r--r-- | block/genhd.c | 2055 |
1 files changed, 2055 insertions, 0 deletions
diff --git a/block/genhd.c b/block/genhd.c new file mode 100644 index 000000000..27a410d31 --- /dev/null +++ b/block/genhd.c @@ -0,0 +1,2055 @@ +/* + * 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/backing-dev.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/mutex.h> +#include <linux/idr.h> +#include <linux/log2.h> +#include <linux/pm_runtime.h> +#include <linux/badblocks.h> + +#include "blk.h" + +static DEFINE_MUTEX(block_class_lock); +struct kobject *block_depr; + +/* for extended dynamic devt allocation, currently only one major is used */ +#define NR_EXT_DEVT (1 << MINORBITS) + +/* For extended devt allocation. ext_devt_lock prevents look up + * results from going away underneath its user. + */ +static DEFINE_SPINLOCK(ext_devt_lock); +static DEFINE_IDR(ext_devt_idr); + +static const struct device_type disk_type; + +static void disk_check_events(struct disk_events *ev, + unsigned int *clearing_ptr); +static void disk_alloc_events(struct gendisk *disk); +static void disk_add_events(struct gendisk *disk); +static void disk_del_events(struct gendisk *disk); +static void disk_release_events(struct gendisk *disk); + +void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw) +{ + if (q->mq_ops) + return; + + atomic_inc(&part->in_flight[rw]); + if (part->partno) + atomic_inc(&part_to_disk(part)->part0.in_flight[rw]); +} + +void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw) +{ + if (q->mq_ops) + return; + + atomic_dec(&part->in_flight[rw]); + if (part->partno) + atomic_dec(&part_to_disk(part)->part0.in_flight[rw]); +} + +void part_in_flight(struct request_queue *q, struct hd_struct *part, + unsigned int inflight[2]) +{ + if (q->mq_ops) { + blk_mq_in_flight(q, part, inflight); + return; + } + + inflight[0] = atomic_read(&part->in_flight[0]) + + atomic_read(&part->in_flight[1]); + if (part->partno) { + part = &part_to_disk(part)->part0; + inflight[1] = atomic_read(&part->in_flight[0]) + + atomic_read(&part->in_flight[1]); + } +} + +void part_in_flight_rw(struct request_queue *q, struct hd_struct *part, + unsigned int inflight[2]) +{ + if (q->mq_ops) { + blk_mq_in_flight_rw(q, part, inflight); + return; + } + + inflight[0] = atomic_read(&part->in_flight[0]); + inflight[1] = atomic_read(&part->in_flight[1]); +} + +struct hd_struct *__disk_get_part(struct gendisk *disk, int partno) +{ + struct disk_part_tbl *ptbl = rcu_dereference(disk->part_tbl); + + if (unlikely(partno < 0 || partno >= ptbl->len)) + return NULL; + return rcu_dereference(ptbl->part[partno]); +} + +/** + * 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; + + rcu_read_lock(); + part = __disk_get_part(disk, 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 | DISK_PITER_INCL_EMPTY_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 | + DISK_PITER_INCL_EMPTY_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; + get_device(part_to_dev(part)); + piter->part = part; + if (!part_nr_sects_read(part) && + !(piter->flags & DISK_PITER_INCL_EMPTY) && + !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 && + piter->idx == 0)) { + put_device(part_to_dev(part)); + piter->part = NULL; + continue; + } + + 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); + +static inline int sector_in_part(struct hd_struct *part, sector_t sector) +{ + return part->start_sect <= sector && + sector < part->start_sect + part_nr_sects_read(part); +} + +/** + * 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; + struct hd_struct *part; + int i; + + ptbl = rcu_dereference(disk->part_tbl); + + part = rcu_dereference(ptbl->last_lookup); + if (part && sector_in_part(part, sector)) + return part; + + for (i = 1; i < ptbl->len; i++) { + part = rcu_dereference(ptbl->part[i]); + + if (part && sector_in_part(part, sector)) { + rcu_assign_pointer(ptbl->last_lookup, part); + return part; + } + } + return &disk->part0; +} +EXPORT_SYMBOL_GPL(disk_map_sector_rcu); + +/* + * Can be deleted altogether. Later. + * + */ +#define BLKDEV_MAJOR_HASH_SIZE 255 +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(unsigned 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; + + mutex_lock(&block_class_lock); + for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next) + if (dp->major == offset) + seq_printf(seqf, "%3d %s\n", dp->major, dp->name); + mutex_unlock(&block_class_lock); +} +#endif /* CONFIG_PROC_FS */ + +/** + * register_blkdev - register a new block device + * + * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If + * @major = 0, try to allocate any unused major number. + * @name: the name of the new block device as a zero terminated string + * + * The @name must be unique within the system. + * + * The return value depends on the @major input parameter: + * + * - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1] + * then the function returns zero on success, or a negative error code + * - if any unused major number was requested with @major = 0 parameter + * then the return value is the allocated major number in range + * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise + * + * See Documentation/admin-guide/devices.txt for the list of allocated + * major numbers. + */ +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; + } + + if (major >= BLKDEV_MAJOR_MAX) { + pr_err("register_blkdev: major requested (%u) is greater than the maximum (%u) for %s\n", + major, BLKDEV_MAJOR_MAX-1, name); + + ret = -EINVAL; + goto out; + } + + 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 %u 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; + + /* in consecutive minor range? */ + if (part->partno < disk->minors) { + *devt = MKDEV(disk->major, disk->first_minor + part->partno); + return 0; + } + + /* allocate ext devt */ + idr_preload(GFP_KERNEL); + + spin_lock_bh(&ext_devt_lock); + idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT); + spin_unlock_bh(&ext_devt_lock); + + idr_preload_end(); + if (idx < 0) + return idx == -ENOSPC ? -EBUSY : idx; + + *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) +{ + if (devt == MKDEV(0, 0)) + return; + + if (MAJOR(devt) == BLOCK_EXT_MAJOR) { + spin_lock_bh(&ext_devt_lock); + idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); + spin_unlock_bh(&ext_devt_lock); + } +} + +/** + * We invalidate devt by assigning NULL pointer for devt in idr. + */ +void blk_invalidate_devt(dev_t devt) +{ + if (MAJOR(devt) == BLOCK_EXT_MAJOR) { + spin_lock_bh(&ext_devt_lock); + idr_replace(&ext_devt_idr, NULL, blk_mangle_minor(MINOR(devt))); + spin_unlock_bh(&ext_devt_lock); + } +} + +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_and_module(p)) + return -1; + return 0; +} + +static void register_disk(struct device *parent, struct gendisk *disk, + const struct attribute_group **groups) +{ + struct device *ddev = disk_to_dev(disk); + struct block_device *bdev; + struct disk_part_iter piter; + struct hd_struct *part; + int err; + + ddev->parent = parent; + + dev_set_name(ddev, "%s", disk->disk_name); + + /* delay uevents, until we scanned partition table */ + dev_set_uevent_suppress(ddev, 1); + + if (groups) { + WARN_ON(ddev->groups); + ddev->groups = groups; + } + if (device_add(ddev)) + return; + if (!sysfs_deprecated) { + err = sysfs_create_link(block_depr, &ddev->kobj, + kobject_name(&ddev->kobj)); + if (err) { + device_del(ddev); + return; + } + } + + /* + * avoid probable deadlock caused by allocating memory with + * GFP_KERNEL in runtime_resume callback of its all ancestor + * devices + */ + pm_runtime_set_memalloc_noio(ddev, true); + + disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj); + disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj); + + if (disk->flags & GENHD_FL_HIDDEN) + return; + + /* No minors to use for partitions */ + if (!disk_part_scan_enabled(disk)) + goto exit; + + /* No such device (e.g., media were just removed) */ + if (!get_capacity(disk)) + goto exit; + + bdev = bdget_disk(disk, 0); + if (!bdev) + goto exit; + + bdev->bd_invalidated = 1; + err = blkdev_get(bdev, FMODE_READ, NULL); + if (err < 0) + goto exit; + blkdev_put(bdev, FMODE_READ); + +exit: + /* announce disk after possible partitions are created */ + dev_set_uevent_suppress(ddev, 0); + kobject_uevent(&ddev->kobj, KOBJ_ADD); + + /* announce possible partitions */ + disk_part_iter_init(&piter, disk, 0); + while ((part = disk_part_iter_next(&piter))) + kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD); + disk_part_iter_exit(&piter); + + if (disk->queue->backing_dev_info->dev) { + err = sysfs_create_link(&ddev->kobj, + &disk->queue->backing_dev_info->dev->kobj, + "bdi"); + WARN_ON(err); + } +} + +/** + * __device_add_disk - add disk information to kernel list + * @parent: parent device for the disk + * @disk: per-device partitioning information + * @groups: Additional per-device sysfs groups + * @register_queue: register the queue if set to true + * + * This function registers the partitioning information in @disk + * with the kernel. + * + * FIXME: error handling + */ +static void __device_add_disk(struct device *parent, struct gendisk *disk, + const struct attribute_group **groups, + bool register_queue) +{ + 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 | GENHD_FL_HIDDEN))); + + disk->flags |= GENHD_FL_UP; + + retval = blk_alloc_devt(&disk->part0, &devt); + if (retval) { + WARN_ON(1); + return; + } + disk->major = MAJOR(devt); + disk->first_minor = MINOR(devt); + + disk_alloc_events(disk); + + if (disk->flags & GENHD_FL_HIDDEN) { + /* + * Don't let hidden disks show up in /proc/partitions, + * and don't bother scanning for partitions either. + */ + disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO; + disk->flags |= GENHD_FL_NO_PART_SCAN; + } else { + int ret; + + /* Register BDI before referencing it from bdev */ + disk_to_dev(disk)->devt = devt; + ret = bdi_register_owner(disk->queue->backing_dev_info, + disk_to_dev(disk)); + WARN_ON(ret); + blk_register_region(disk_devt(disk), disk->minors, NULL, + exact_match, exact_lock, disk); + } + register_disk(parent, disk, groups); + if (register_queue) + blk_register_queue(disk); + + /* + * Take an extra ref on queue which will be put on disk_release() + * so that it sticks around as long as @disk is there. + */ + WARN_ON_ONCE(!blk_get_queue(disk->queue)); + + disk_add_events(disk); + blk_integrity_add(disk); +} + +void device_add_disk(struct device *parent, struct gendisk *disk, + const struct attribute_group **groups) + +{ + __device_add_disk(parent, disk, groups, true); +} +EXPORT_SYMBOL(device_add_disk); + +void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk) +{ + __device_add_disk(parent, disk, NULL, false); +} +EXPORT_SYMBOL(device_add_disk_no_queue_reg); + +void del_gendisk(struct gendisk *disk) +{ + struct disk_part_iter piter; + struct hd_struct *part; + + blk_integrity_del(disk); + disk_del_events(disk); + + /* + * Block lookups of the disk until all bdevs are unhashed and the + * disk is marked as dead (GENHD_FL_UP cleared). + */ + down_write(&disk->lookup_sem); + /* invalidate stuff */ + disk_part_iter_init(&piter, disk, + DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE); + while ((part = disk_part_iter_next(&piter))) { + invalidate_partition(disk, part->partno); + bdev_unhash_inode(part_devt(part)); + delete_partition(disk, part->partno); + } + disk_part_iter_exit(&piter); + + invalidate_partition(disk, 0); + bdev_unhash_inode(disk_devt(disk)); + set_capacity(disk, 0); + disk->flags &= ~GENHD_FL_UP; + up_write(&disk->lookup_sem); + + if (!(disk->flags & GENHD_FL_HIDDEN)) + sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); + if (disk->queue) { + /* + * Unregister bdi before releasing device numbers (as they can + * get reused and we'd get clashes in sysfs). + */ + if (!(disk->flags & GENHD_FL_HIDDEN)) + bdi_unregister(disk->queue->backing_dev_info); + blk_unregister_queue(disk); + } else { + WARN_ON(1); + } + + if (!(disk->flags & GENHD_FL_HIDDEN)) + blk_unregister_region(disk_devt(disk), disk->minors); + /* + * Remove gendisk pointer from idr so that it cannot be looked up + * while RCU period before freeing gendisk is running to prevent + * use-after-free issues. Note that the device number stays + * "in-use" until we really free the gendisk. + */ + blk_invalidate_devt(disk_devt(disk)); + + kobject_put(disk->part0.holder_dir); + kobject_put(disk->slave_dir); + + part_stat_set_all(&disk->part0, 0); + disk->part0.stamp = 0; + if (!sysfs_deprecated) + sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); + pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); + device_del(disk_to_dev(disk)); +} +EXPORT_SYMBOL(del_gendisk); + +/* sysfs access to bad-blocks list. */ +static ssize_t disk_badblocks_show(struct device *dev, + struct device_attribute *attr, + char *page) +{ + struct gendisk *disk = dev_to_disk(dev); + + if (!disk->bb) + return sprintf(page, "\n"); + + return badblocks_show(disk->bb, page, 0); +} + +static ssize_t disk_badblocks_store(struct device *dev, + struct device_attribute *attr, + const char *page, size_t len) +{ + struct gendisk *disk = dev_to_disk(dev); + + if (!disk->bb) + return -ENXIO; + + return badblocks_store(disk->bb, page, len, 0); +} + +/** + * 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; + + spin_lock_bh(&ext_devt_lock); + part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); + if (part && get_disk_and_module(part_to_disk(part))) { + *partno = part->partno; + disk = part_to_disk(part); + } + spin_unlock_bh(&ext_devt_lock); + } + + if (!disk) + return NULL; + + /* + * Synchronize with del_gendisk() to not return disk that is being + * destroyed. + */ + down_read(&disk->lookup_sem); + if (unlikely((disk->flags & GENHD_FL_HIDDEN) || + !(disk->flags & GENHD_FL_UP))) { + up_read(&disk->lookup_sem); + put_disk_and_module(disk); + disk = NULL; + } else { + up_read(&disk->lookup_sem); + } + return disk; +} +EXPORT_SYMBOL(get_gendisk); + +/** + * 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 + * suppressed + */ + 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 %s", is_part0 ? "" : " ", + bdevt_str(part_devt(part), devt_buf), + (unsigned long long)part_nr_sects_read(part) >> 1 + , disk_name(disk, part->partno, name_buf), + part->info ? part->info->uuid : ""); + if (is_part0) { + if (dev->parent && dev->parent->driver) + printk(" driver: %s\n", + dev->parent->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); + seqf->private = NULL; + } +} + +static void *show_partition_start(struct seq_file *seqf, loff_t *pos) +{ + void *p; + + p = disk_seqf_start(seqf, pos); + if (!IS_ERR_OR_NULL(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_max_parts(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_read(part) >> 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 +}; +#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"); + + /* create top-level block dir */ + if (!sysfs_deprecated) + block_depr = kobject_create_and_add("block", NULL); + 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_hidden_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_HIDDEN ? 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 ssize_t disk_alignment_offset_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue)); +} + +static ssize_t disk_discard_alignment_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue)); +} + +static DEVICE_ATTR(range, 0444, disk_range_show, NULL); +static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL); +static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL); +static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL); +static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL); +static DEVICE_ATTR(size, 0444, part_size_show, NULL); +static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL); +static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL); +static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL); +static DEVICE_ATTR(stat, 0444, part_stat_show, NULL); +static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL); +static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store); +#ifdef CONFIG_FAIL_MAKE_REQUEST +static struct device_attribute dev_attr_fail = + __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store); +#endif +#ifdef CONFIG_FAIL_IO_TIMEOUT +static struct device_attribute dev_attr_fail_timeout = + __ATTR(io-timeout-fail, 0644, 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_hidden.attr, + &dev_attr_ro.attr, + &dev_attr_size.attr, + &dev_attr_alignment_offset.attr, + &dev_attr_discard_alignment.attr, + &dev_attr_capability.attr, + &dev_attr_stat.attr, + &dev_attr_inflight.attr, + &dev_attr_badblocks.attr, +#ifdef CONFIG_FAIL_MAKE_REQUEST + &dev_attr_fail.attr, +#endif +#ifdef CONFIG_FAIL_IO_TIMEOUT + &dev_attr_fail_timeout.attr, +#endif + NULL +}; + +static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n) +{ + struct device *dev = container_of(kobj, typeof(*dev), kobj); + struct gendisk *disk = dev_to_disk(dev); + + if (a == &dev_attr_badblocks.attr && !disk->bb) + return 0; + return a->mode; +} + +static struct attribute_group disk_attr_group = { + .attrs = disk_attrs, + .is_visible = disk_visible, +}; + +static const struct attribute_group *disk_attr_groups[] = { + &disk_attr_group, + NULL +}; + +/** + * 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_mutex locked or the caller is the only user of @disk. + */ +static void disk_replace_part_tbl(struct gendisk *disk, + struct disk_part_tbl *new_ptbl) +{ + struct disk_part_tbl *old_ptbl = + rcu_dereference_protected(disk->part_tbl, 1); + + rcu_assign_pointer(disk->part_tbl, new_ptbl); + + if (old_ptbl) { + rcu_assign_pointer(old_ptbl->last_lookup, NULL); + kfree_rcu(old_ptbl, rcu_head); + } +} + +/** + * 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 or the caller is the only user of @disk. + * 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 = + rcu_dereference_protected(disk->part_tbl, 1); + struct disk_part_tbl *new_ptbl; + int len = old_ptbl ? old_ptbl->len : 0; + int i, target; + size_t size; + + /* + * check for int overflow, since we can get here from blkpg_ioctl() + * with a user passed 'partno'. + */ + target = partno + 1; + if (target < 0) + return -EINVAL; + + /* 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; + + 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); + + blk_free_devt(dev->devt); + disk_release_events(disk); + kfree(disk->random); + disk_replace_part_tbl(disk, NULL); + hd_free_part(&disk->part0); + if (disk->queue) + blk_put_queue(disk->queue); + kfree(disk); +} +struct class block_class = { + .name = "block", +}; + +static char *block_devnode(struct device *dev, umode_t *mode, + kuid_t *uid, kgid_t *gid) +{ + struct gendisk *disk = dev_to_disk(dev); + + if (disk->devnode) + return disk->devnode(disk, mode); + return NULL; +} + +static const struct device_type disk_type = { + .name = "disk", + .groups = disk_attr_groups, + .release = disk_release, + .devnode = block_devnode, +}; + +#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]; + unsigned int inflight[2]; + 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_EMPTY_PART0); + while ((hd = disk_part_iter_next(&piter))) { + cpu = part_stat_lock(); + part_round_stats(gp->queue, cpu, hd); + part_stat_unlock(); + part_in_flight(gp->queue, hd, inflight); + seq_printf(seqf, "%4d %7d %s " + "%lu %lu %lu %u " + "%lu %lu %lu %u " + "%u %u %u " + "%lu %lu %lu %u\n", + MAJOR(part_devt(hd)), MINOR(part_devt(hd)), + disk_name(gp, hd->partno, buf), + part_stat_read(hd, ios[STAT_READ]), + part_stat_read(hd, merges[STAT_READ]), + part_stat_read(hd, sectors[STAT_READ]), + (unsigned int)part_stat_read_msecs(hd, STAT_READ), + part_stat_read(hd, ios[STAT_WRITE]), + part_stat_read(hd, merges[STAT_WRITE]), + part_stat_read(hd, sectors[STAT_WRITE]), + (unsigned int)part_stat_read_msecs(hd, STAT_WRITE), + inflight[0], + jiffies_to_msecs(part_stat_read(hd, io_ticks)), + jiffies_to_msecs(part_stat_read(hd, time_in_queue)), + part_stat_read(hd, ios[STAT_DISCARD]), + part_stat_read(hd, merges[STAT_DISCARD]), + part_stat_read(hd, sectors[STAT_DISCARD]), + (unsigned int)part_stat_read_msecs(hd, STAT_DISCARD) + ); + } + 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 __init proc_genhd_init(void) +{ + proc_create_seq("diskstats", 0, NULL, &diskstats_op); + proc_create_seq("partitions", 0, NULL, &partitions_op); + return 0; +} +module_init(proc_genhd_init); +#endif /* CONFIG_PROC_FS */ + +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_name(dev), name)) + continue; + + if (partno < disk->minors) { + /* We need to return the right devno, even + * if the partition doesn't exist yet. + */ + devt = MKDEV(MAJOR(dev->devt), + MINOR(dev->devt) + partno); + break; + } + 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_node(int minors, int node_id) +{ + struct gendisk *disk; + struct disk_part_tbl *ptbl; + + if (minors > DISK_MAX_PARTS) { + printk(KERN_ERR + "block: can't allocate more than %d partitions\n", + DISK_MAX_PARTS); + minors = DISK_MAX_PARTS; + } + + disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id); + if (disk) { + if (!init_part_stats(&disk->part0)) { + kfree(disk); + return NULL; + } + init_rwsem(&disk->lookup_sem); + disk->node_id = node_id; + if (disk_expand_part_tbl(disk, 0)) { + free_part_stats(&disk->part0); + kfree(disk); + return NULL; + } + ptbl = rcu_dereference_protected(disk->part_tbl, 1); + rcu_assign_pointer(ptbl->part[0], &disk->part0); + + /* + * set_capacity() and get_capacity() currently don't use + * seqcounter to read/update the part0->nr_sects. Still init + * the counter as we can read the sectors in IO submission + * patch using seqence counters. + * + * TODO: Ideally set_capacity() and get_capacity() should be + * converted to make use of bd_mutex and sequence counters. + */ + seqcount_init(&disk->part0.nr_sects_seq); + if (hd_ref_init(&disk->part0)) { + hd_free_part(&disk->part0); + kfree(disk); + return NULL; + } + + 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)); + } + return disk; +} +EXPORT_SYMBOL(__alloc_disk_node); + +struct kobject *get_disk_and_module(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_unless_zero(&disk_to_dev(disk)->kobj); + if (kobj == NULL) { + module_put(owner); + return NULL; + } + return kobj; + +} +EXPORT_SYMBOL(get_disk_and_module); + +void put_disk(struct gendisk *disk) +{ + if (disk) + kobject_put(&disk_to_dev(disk)->kobj); +} +EXPORT_SYMBOL(put_disk); + +/* + * This is a counterpart of get_disk_and_module() and thus also of + * get_gendisk(). + */ +void put_disk_and_module(struct gendisk *disk) +{ + if (disk) { + struct module *owner = disk->fops->owner; + + put_disk(disk); + module_put(owner); + } +} +EXPORT_SYMBOL(put_disk_and_module); + +static void set_disk_ro_uevent(struct gendisk *gd, int ro) +{ + char event[] = "DISK_RO=1"; + char *envp[] = { event, NULL }; + + if (!ro) + event[8] = '0'; + kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); +} + +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; + + if (disk->part0.policy != flag) { + set_disk_ro_uevent(disk, flag); + disk->part0.policy = flag; + } + + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); + 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, true); + bdput(bdev); + } + return res; +} + +EXPORT_SYMBOL(invalidate_partition); + +/* + * Disk events - monitor disk events like media change and eject request. + */ +struct disk_events { + struct list_head node; /* all disk_event's */ + struct gendisk *disk; /* the associated disk */ + spinlock_t lock; + + struct mutex block_mutex; /* protects blocking */ + int block; /* event blocking depth */ + unsigned int pending; /* events already sent out */ + unsigned int clearing; /* events being cleared */ + + long poll_msecs; /* interval, -1 for default */ + struct delayed_work dwork; +}; + +static const char *disk_events_strs[] = { + [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "media_change", + [ilog2(DISK_EVENT_EJECT_REQUEST)] = "eject_request", +}; + +static char *disk_uevents[] = { + [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "DISK_MEDIA_CHANGE=1", + [ilog2(DISK_EVENT_EJECT_REQUEST)] = "DISK_EJECT_REQUEST=1", +}; + +/* list of all disk_events */ +static DEFINE_MUTEX(disk_events_mutex); +static LIST_HEAD(disk_events); + +/* disable in-kernel polling by default */ +static unsigned long disk_events_dfl_poll_msecs; + +static unsigned long disk_events_poll_jiffies(struct gendisk *disk) +{ + struct disk_events *ev = disk->ev; + long intv_msecs = 0; + + /* + * If device-specific poll interval is set, always use it. If + * the default is being used, poll iff there are events which + * can't be monitored asynchronously. + */ + if (ev->poll_msecs >= 0) + intv_msecs = ev->poll_msecs; + else if (disk->events & ~disk->async_events) + intv_msecs = disk_events_dfl_poll_msecs; + + return msecs_to_jiffies(intv_msecs); +} + +/** + * disk_block_events - block and flush disk event checking + * @disk: disk to block events for + * + * On return from this function, it is guaranteed that event checking + * isn't in progress and won't happen until unblocked by + * disk_unblock_events(). Events blocking is counted and the actual + * unblocking happens after the matching number of unblocks are done. + * + * Note that this intentionally does not block event checking from + * disk_clear_events(). + * + * CONTEXT: + * Might sleep. + */ +void disk_block_events(struct gendisk *disk) +{ + struct disk_events *ev = disk->ev; + unsigned long flags; + bool cancel; + + if (!ev) + return; + + /* + * Outer mutex ensures that the first blocker completes canceling + * the event work before further blockers are allowed to finish. + */ + mutex_lock(&ev->block_mutex); + + spin_lock_irqsave(&ev->lock, flags); + cancel = !ev->block++; + spin_unlock_irqrestore(&ev->lock, flags); + + if (cancel) + cancel_delayed_work_sync(&disk->ev->dwork); + + mutex_unlock(&ev->block_mutex); +} + +static void __disk_unblock_events(struct gendisk *disk, bool check_now) +{ + struct disk_events *ev = disk->ev; + unsigned long intv; + unsigned long flags; + + spin_lock_irqsave(&ev->lock, flags); + + if (WARN_ON_ONCE(ev->block <= 0)) + goto out_unlock; + + if (--ev->block) + goto out_unlock; + + intv = disk_events_poll_jiffies(disk); + if (check_now) + queue_delayed_work(system_freezable_power_efficient_wq, + &ev->dwork, 0); + else if (intv) + queue_delayed_work(system_freezable_power_efficient_wq, + &ev->dwork, intv); +out_unlock: + spin_unlock_irqrestore(&ev->lock, flags); +} + +/** + * disk_unblock_events - unblock disk event checking + * @disk: disk to unblock events for + * + * Undo disk_block_events(). When the block count reaches zero, it + * starts events polling if configured. + * + * CONTEXT: + * Don't care. Safe to call from irq context. + */ +void disk_unblock_events(struct gendisk *disk) +{ + if (disk->ev) + __disk_unblock_events(disk, false); +} + +/** + * disk_flush_events - schedule immediate event checking and flushing + * @disk: disk to check and flush events for + * @mask: events to flush + * + * Schedule immediate event checking on @disk if not blocked. Events in + * @mask are scheduled to be cleared from the driver. Note that this + * doesn't clear the events from @disk->ev. + * + * CONTEXT: + * If @mask is non-zero must be called with bdev->bd_mutex held. + */ +void disk_flush_events(struct gendisk *disk, unsigned int mask) +{ + struct disk_events *ev = disk->ev; + + if (!ev) + return; + + spin_lock_irq(&ev->lock); + ev->clearing |= mask; + if (!ev->block) + mod_delayed_work(system_freezable_power_efficient_wq, + &ev->dwork, 0); + spin_unlock_irq(&ev->lock); +} + +/** + * disk_clear_events - synchronously check, clear and return pending events + * @disk: disk to fetch and clear events from + * @mask: mask of events to be fetched and cleared + * + * Disk events are synchronously checked and pending events in @mask + * are cleared and returned. This ignores the block count. + * + * CONTEXT: + * Might sleep. + */ +unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask) +{ + const struct block_device_operations *bdops = disk->fops; + struct disk_events *ev = disk->ev; + unsigned int pending; + unsigned int clearing = mask; + + if (!ev) { + /* for drivers still using the old ->media_changed method */ + if ((mask & DISK_EVENT_MEDIA_CHANGE) && + bdops->media_changed && bdops->media_changed(disk)) + return DISK_EVENT_MEDIA_CHANGE; + return 0; + } + + disk_block_events(disk); + + /* + * store the union of mask and ev->clearing on the stack so that the + * race with disk_flush_events does not cause ambiguity (ev->clearing + * can still be modified even if events are blocked). + */ + spin_lock_irq(&ev->lock); + clearing |= ev->clearing; + ev->clearing = 0; + spin_unlock_irq(&ev->lock); + + disk_check_events(ev, &clearing); + /* + * if ev->clearing is not 0, the disk_flush_events got called in the + * middle of this function, so we want to run the workfn without delay. + */ + __disk_unblock_events(disk, ev->clearing ? true : false); + + /* then, fetch and clear pending events */ + spin_lock_irq(&ev->lock); + pending = ev->pending & mask; + ev->pending &= ~mask; + spin_unlock_irq(&ev->lock); + WARN_ON_ONCE(clearing & mask); + + return pending; +} + +/* + * Separate this part out so that a different pointer for clearing_ptr can be + * passed in for disk_clear_events. + */ +static void disk_events_workfn(struct work_struct *work) +{ + struct delayed_work *dwork = to_delayed_work(work); + struct disk_events *ev = container_of(dwork, struct disk_events, dwork); + + disk_check_events(ev, &ev->clearing); +} + +static void disk_check_events(struct disk_events *ev, + unsigned int *clearing_ptr) +{ + struct gendisk *disk = ev->disk; + char *envp[ARRAY_SIZE(disk_uevents) + 1] = { }; + unsigned int clearing = *clearing_ptr; + unsigned int events; + unsigned long intv; + int nr_events = 0, i; + + /* check events */ + events = disk->fops->check_events(disk, clearing); + + /* accumulate pending events and schedule next poll if necessary */ + spin_lock_irq(&ev->lock); + + events &= ~ev->pending; + ev->pending |= events; + *clearing_ptr &= ~clearing; + + intv = disk_events_poll_jiffies(disk); + if (!ev->block && intv) + queue_delayed_work(system_freezable_power_efficient_wq, + &ev->dwork, intv); + + spin_unlock_irq(&ev->lock); + + /* + * Tell userland about new events. Only the events listed in + * @disk->events are reported. Unlisted events are processed the + * same internally but never get reported to userland. + */ + for (i = 0; i < ARRAY_SIZE(disk_uevents); i++) + if (events & disk->events & (1 << i)) + envp[nr_events++] = disk_uevents[i]; + + if (nr_events) + kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); +} + +/* + * A disk events enabled device has the following sysfs nodes under + * its /sys/block/X/ directory. + * + * events : list of all supported events + * events_async : list of events which can be detected w/o polling + * events_poll_msecs : polling interval, 0: disable, -1: system default + */ +static ssize_t __disk_events_show(unsigned int events, char *buf) +{ + const char *delim = ""; + ssize_t pos = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++) + if (events & (1 << i)) { + pos += sprintf(buf + pos, "%s%s", + delim, disk_events_strs[i]); + delim = " "; + } + if (pos) + pos += sprintf(buf + pos, "\n"); + return pos; +} + +static ssize_t disk_events_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return __disk_events_show(disk->events, buf); +} + +static ssize_t disk_events_async_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return __disk_events_show(disk->async_events, buf); +} + +static ssize_t disk_events_poll_msecs_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%ld\n", disk->ev->poll_msecs); +} + +static ssize_t disk_events_poll_msecs_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct gendisk *disk = dev_to_disk(dev); + long intv; + + if (!count || !sscanf(buf, "%ld", &intv)) + return -EINVAL; + + if (intv < 0 && intv != -1) + return -EINVAL; + + disk_block_events(disk); + disk->ev->poll_msecs = intv; + __disk_unblock_events(disk, true); + + return count; +} + +static const DEVICE_ATTR(events, 0444, disk_events_show, NULL); +static const DEVICE_ATTR(events_async, 0444, disk_events_async_show, NULL); +static const DEVICE_ATTR(events_poll_msecs, 0644, + disk_events_poll_msecs_show, + disk_events_poll_msecs_store); + +static const struct attribute *disk_events_attrs[] = { + &dev_attr_events.attr, + &dev_attr_events_async.attr, + &dev_attr_events_poll_msecs.attr, + NULL, +}; + +/* + * The default polling interval can be specified by the kernel + * parameter block.events_dfl_poll_msecs which defaults to 0 + * (disable). This can also be modified runtime by writing to + * /sys/module/block/events_dfl_poll_msecs. + */ +static int disk_events_set_dfl_poll_msecs(const char *val, + const struct kernel_param *kp) +{ + struct disk_events *ev; + int ret; + + ret = param_set_ulong(val, kp); + if (ret < 0) + return ret; + + mutex_lock(&disk_events_mutex); + + list_for_each_entry(ev, &disk_events, node) + disk_flush_events(ev->disk, 0); + + mutex_unlock(&disk_events_mutex); + + return 0; +} + +static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = { + .set = disk_events_set_dfl_poll_msecs, + .get = param_get_ulong, +}; + +#undef MODULE_PARAM_PREFIX +#define MODULE_PARAM_PREFIX "block." + +module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops, + &disk_events_dfl_poll_msecs, 0644); + +/* + * disk_{alloc|add|del|release}_events - initialize and destroy disk_events. + */ +static void disk_alloc_events(struct gendisk *disk) +{ + struct disk_events *ev; + + if (!disk->fops->check_events) + return; + + ev = kzalloc(sizeof(*ev), GFP_KERNEL); + if (!ev) { + pr_warn("%s: failed to initialize events\n", disk->disk_name); + return; + } + + INIT_LIST_HEAD(&ev->node); + ev->disk = disk; + spin_lock_init(&ev->lock); + mutex_init(&ev->block_mutex); + ev->block = 1; + ev->poll_msecs = -1; + INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn); + + disk->ev = ev; +} + +static void disk_add_events(struct gendisk *disk) +{ + if (!disk->ev) + return; + + /* FIXME: error handling */ + if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0) + pr_warn("%s: failed to create sysfs files for events\n", + disk->disk_name); + + mutex_lock(&disk_events_mutex); + list_add_tail(&disk->ev->node, &disk_events); + mutex_unlock(&disk_events_mutex); + + /* + * Block count is initialized to 1 and the following initial + * unblock kicks it into action. + */ + __disk_unblock_events(disk, true); +} + +static void disk_del_events(struct gendisk *disk) +{ + if (!disk->ev) + return; + + disk_block_events(disk); + + mutex_lock(&disk_events_mutex); + list_del_init(&disk->ev->node); + mutex_unlock(&disk_events_mutex); + + sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs); +} + +static void disk_release_events(struct gendisk *disk) +{ + /* the block count should be 1 from disk_del_events() */ + WARN_ON_ONCE(disk->ev && disk->ev->block != 1); + kfree(disk->ev); +} |