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genhd.c
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genhd.c
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// SPDX-License-Identifier: GPL-2.0
/*
* gendisk handling
*/
#include <linux/module.h>
#include <linux/ctype.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);
static 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);
/*
* Set disk capacity and notify if the size is not currently
* zero and will not be set to zero
*/
void set_capacity_revalidate_and_notify(struct gendisk *disk, sector_t size,
bool revalidate)
{
sector_t capacity = get_capacity(disk);
set_capacity(disk, size);
if (revalidate)
revalidate_disk(disk);
if (capacity != size && capacity != 0 && size != 0) {
char *envp[] = { "RESIZE=1", NULL };
kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
}
}
EXPORT_SYMBOL_GPL(set_capacity_revalidate_and_notify);
/*
* Format the device name of the indicated disk into the supplied buffer and
* return a pointer to that same buffer for convenience.
*/
char *disk_name(struct gendisk *hd, int partno, char *buf)
{
if (!partno)
snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
else
snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
return buf;
}
const char *bdevname(struct block_device *bdev, char *buf)
{
return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
}
EXPORT_SYMBOL(bdevname);
#ifdef CONFIG_SMP
static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)
{
int cpu;
memset(stat, 0, sizeof(struct disk_stats));
for_each_possible_cpu(cpu) {
struct disk_stats *ptr = per_cpu_ptr(part->dkstats, cpu);
int group;
for (group = 0; group < NR_STAT_GROUPS; group++) {
stat->nsecs[group] += ptr->nsecs[group];
stat->sectors[group] += ptr->sectors[group];
stat->ios[group] += ptr->ios[group];
stat->merges[group] += ptr->merges[group];
}
stat->io_ticks += ptr->io_ticks;
}
}
#else /* CONFIG_SMP */
static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)
{
memcpy(stat, &part->dkstats, sizeof(struct disk_stats));
}
#endif /* CONFIG_SMP */
void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
{
if (queue_is_mq(q))
return;
part_stat_local_inc(part, in_flight[rw]);
if (part->partno)
part_stat_local_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 (queue_is_mq(q))
return;
part_stat_local_dec(part, in_flight[rw]);
if (part->partno)
part_stat_local_dec(&part_to_disk(part)->part0, in_flight[rw]);
}
static unsigned int part_in_flight(struct request_queue *q,
struct hd_struct *part)
{
int cpu;
unsigned int inflight;
if (queue_is_mq(q)) {
return blk_mq_in_flight(q, part);
}
inflight = 0;
for_each_possible_cpu(cpu) {
inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +
part_stat_local_read_cpu(part, in_flight[1], cpu);
}
if ((int)inflight < 0)
inflight = 0;
return inflight;
}
static void part_in_flight_rw(struct request_queue *q, struct hd_struct *part,
unsigned int inflight[2])
{
int cpu;
if (queue_is_mq(q)) {
blk_mq_in_flight_rw(q, part, inflight);
return;
}
inflight[0] = 0;
inflight[1] = 0;
for_each_possible_cpu(cpu) {
inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);
inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);
}
if ((int)inflight[0] < 0)
inflight[0] = 0;
if ((int)inflight[1] < 0)
inflight[1] = 0;
}
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;
}
/**
* 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;
if (!part_nr_sects_read(part) &&
!(piter->flags & DISK_PITER_INCL_EMPTY) &&
!(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
piter->idx == 0))
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);
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("%s: failed to get major for %s\n",
__func__, name);
ret = -EBUSY;
goto out;
}
major = index;
ret = major;
}
if (major >= BLKDEV_MAJOR_MAX) {
pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",
__func__, 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) {
dev_set_uevent_suppress(ddev, 0);
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;
/*
* The disk queue should now be all set with enough information about
* the device for the elevator code to pick an adequate default
* elevator if one is needed, that is, for devices requesting queue
* registration.
*/
if (register_queue)
elevator_init_mq(disk->queue);
/* 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)
{