linux/block/genhd.c
Linus Torvalds 71a7507afb Driver Core changes for 6.2-rc1
Here is the set of driver core and kernfs changes for 6.2-rc1.
 
 The "big" change in here is the addition of a new macro,
 container_of_const() that will preserve the "const-ness" of a pointer
 passed into it.
 
 The "problem" of the current container_of() macro is that if you pass in
 a "const *", out of it can comes a non-const pointer unless you
 specifically ask for it.  For many usages, we want to preserve the
 "const" attribute by using the same call.  For a specific example, this
 series changes the kobj_to_dev() macro to use it, allowing it to be used
 no matter what the const value is.  This prevents every subsystem from
 having to declare 2 different individual macros (i.e.
 kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce
 the const value at build time, which having 2 macros would not do
 either.
 
 The driver for all of this have been discussions with the Rust kernel
 developers as to how to properly mark driver core, and kobject, objects
 as being "non-mutable".  The changes to the kobject and driver core in
 this pull request are the result of that, as there are lots of paths
 where kobjects and device pointers are not modified at all, so marking
 them as "const" allows the compiler to enforce this.
 
 So, a nice side affect of the Rust development effort has been already
 to clean up the driver core code to be more obvious about object rules.
 
 All of this has been bike-shedded in quite a lot of detail on lkml with
 different names and implementations resulting in the tiny version we
 have in here, much better than my original proposal.  Lots of subsystem
 maintainers have acked the changes as well.
 
 Other than this change, included in here are smaller stuff like:
   - kernfs fixes and updates to handle lock contention better
   - vmlinux.lds.h fixes and updates
   - sysfs and debugfs documentation updates
   - device property updates
 
 All of these have been in the linux-next tree for quite a while with no
 problems, OTHER than some merge issues with other trees that should be
 obvious when you hit them (block tree deletes a driver that this tree
 modifies, iommufd tree modifies code that this tree also touches).  If
 there are merge problems with these trees, please let me know.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the set of driver core and kernfs changes for 6.2-rc1.

  The "big" change in here is the addition of a new macro,
  container_of_const() that will preserve the "const-ness" of a pointer
  passed into it.

  The "problem" of the current container_of() macro is that if you pass
  in a "const *", out of it can comes a non-const pointer unless you
  specifically ask for it. For many usages, we want to preserve the
  "const" attribute by using the same call. For a specific example, this
  series changes the kobj_to_dev() macro to use it, allowing it to be
  used no matter what the const value is. This prevents every subsystem
  from having to declare 2 different individual macros (i.e.
  kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce
  the const value at build time, which having 2 macros would not do
  either.

  The driver for all of this have been discussions with the Rust kernel
  developers as to how to properly mark driver core, and kobject,
  objects as being "non-mutable". The changes to the kobject and driver
  core in this pull request are the result of that, as there are lots of
  paths where kobjects and device pointers are not modified at all, so
  marking them as "const" allows the compiler to enforce this.

  So, a nice side affect of the Rust development effort has been already
  to clean up the driver core code to be more obvious about object
  rules.

  All of this has been bike-shedded in quite a lot of detail on lkml
  with different names and implementations resulting in the tiny version
  we have in here, much better than my original proposal. Lots of
  subsystem maintainers have acked the changes as well.

  Other than this change, included in here are smaller stuff like:

   - kernfs fixes and updates to handle lock contention better

   - vmlinux.lds.h fixes and updates

   - sysfs and debugfs documentation updates

   - device property updates

  All of these have been in the linux-next tree for quite a while with
  no problems"

* tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits)
  device property: Fix documentation for fwnode_get_next_parent()
  firmware_loader: fix up to_fw_sysfs() to preserve const
  usb.h: take advantage of container_of_const()
  device.h: move kobj_to_dev() to use container_of_const()
  container_of: add container_of_const() that preserves const-ness of the pointer
  driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion.
  driver core: fix up missed scsi/cxlflash class.devnode() conversion.
  driver core: fix up some missing class.devnode() conversions.
  driver core: make struct class.devnode() take a const *
  driver core: make struct class.dev_uevent() take a const *
  cacheinfo: Remove of_node_put() for fw_token
  device property: Add a blank line in Kconfig of tests
  device property: Rename goto label to be more precise
  device property: Move PROPERTY_ENTRY_BOOL() a bit down
  device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*()
  kernfs: fix all kernel-doc warnings and multiple typos
  driver core: pass a const * into of_device_uevent()
  kobject: kset_uevent_ops: make name() callback take a const *
  kobject: kset_uevent_ops: make filter() callback take a const *
  kobject: make kobject_namespace take a const *
  ...
2022-12-16 03:54:54 -08:00

1482 lines
37 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* gendisk handling
*
* Portions Copyright (C) 2020 Christoph Hellwig
*/
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/fs.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/major.h>
#include <linux/mutex.h>
#include <linux/idr.h>
#include <linux/log2.h>
#include <linux/pm_runtime.h>
#include <linux/badblocks.h>
#include <linux/part_stat.h>
#include "blk-throttle.h"
#include "blk.h"
#include "blk-mq-sched.h"
#include "blk-rq-qos.h"
#include "blk-cgroup.h"
static struct kobject *block_depr;
/*
* Unique, monotonically increasing sequential number associated with block
* devices instances (i.e. incremented each time a device is attached).
* Associating uevents with block devices in userspace is difficult and racy:
* the uevent netlink socket is lossy, and on slow and overloaded systems has
* a very high latency.
* Block devices do not have exclusive owners in userspace, any process can set
* one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0
* can be reused again and again).
* A userspace process setting up a block device and watching for its events
* cannot thus reliably tell whether an event relates to the device it just set
* up or another earlier instance with the same name.
* This sequential number allows userspace processes to solve this problem, and
* uniquely associate an uevent to the lifetime to a device.
*/
static atomic64_t diskseq;
/* for extended dynamic devt allocation, currently only one major is used */
#define NR_EXT_DEVT (1 << MINORBITS)
static DEFINE_IDA(ext_devt_ida);
void set_capacity(struct gendisk *disk, sector_t sectors)
{
struct block_device *bdev = disk->part0;
spin_lock(&bdev->bd_size_lock);
i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
bdev->bd_nr_sectors = sectors;
spin_unlock(&bdev->bd_size_lock);
}
EXPORT_SYMBOL(set_capacity);
/*
* Set disk capacity and notify if the size is not currently zero and will not
* be set to zero. Returns true if a uevent was sent, otherwise false.
*/
bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
{
sector_t capacity = get_capacity(disk);
char *envp[] = { "RESIZE=1", NULL };
set_capacity(disk, size);
/*
* Only print a message and send a uevent if the gendisk is user visible
* and alive. This avoids spamming the log and udev when setting the
* initial capacity during probing.
*/
if (size == capacity ||
!disk_live(disk) ||
(disk->flags & GENHD_FL_HIDDEN))
return false;
pr_info("%s: detected capacity change from %lld to %lld\n",
disk->disk_name, capacity, size);
/*
* Historically we did not send a uevent for changes to/from an empty
* device.
*/
if (!capacity || !size)
return false;
kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
return true;
}
EXPORT_SYMBOL_GPL(set_capacity_and_notify);
static void part_stat_read_all(struct block_device *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->bd_stats, 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;
}
}
static unsigned int part_in_flight(struct block_device *part)
{
unsigned int inflight = 0;
int cpu;
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 block_device *part,
unsigned int inflight[2])
{
int cpu;
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;
}
/*
* 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];
#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
void (*probe)(dev_t devt);
#endif
} *major_names[BLKDEV_MAJOR_HASH_SIZE];
static DEFINE_MUTEX(major_names_lock);
static DEFINE_SPINLOCK(major_names_spinlock);
/* 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;
spin_lock(&major_names_spinlock);
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);
spin_unlock(&major_names_spinlock);
}
#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
* @probe: pre-devtmpfs / pre-udev callback used to create disks when their
* pre-created device node is accessed. When a probe call uses
* add_disk() and it fails the driver must cleanup resources. This
* interface may soon be removed.
*
* 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.
*
* Use register_blkdev instead for any new code.
*/
int __register_blkdev(unsigned int major, const char *name,
void (*probe)(dev_t devt))
{
struct blk_major_name **n, *p;
int index, ret = 0;
mutex_lock(&major_names_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;
#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
p->probe = probe;
#endif
strlcpy(p->name, name, sizeof(p->name));
p->next = NULL;
index = major_to_index(major);
spin_lock(&major_names_spinlock);
for (n = &major_names[index]; *n; n = &(*n)->next) {
if ((*n)->major == major)
break;
}
if (!*n)
*n = p;
else
ret = -EBUSY;
spin_unlock(&major_names_spinlock);
if (ret < 0) {
printk("register_blkdev: cannot get major %u for %s\n",
major, name);
kfree(p);
}
out:
mutex_unlock(&major_names_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(&major_names_lock);
spin_lock(&major_names_spinlock);
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;
}
spin_unlock(&major_names_spinlock);
mutex_unlock(&major_names_lock);
kfree(p);
}
EXPORT_SYMBOL(unregister_blkdev);
int blk_alloc_ext_minor(void)
{
int idx;
idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT - 1, GFP_KERNEL);
if (idx == -ENOSPC)
return -EBUSY;
return idx;
}
void blk_free_ext_minor(unsigned int minor)
{
ida_free(&ext_devt_ida, minor);
}
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;
}
void disk_uevent(struct gendisk *disk, enum kobject_action action)
{
struct block_device *part;
unsigned long idx;
rcu_read_lock();
xa_for_each(&disk->part_tbl, idx, part) {
if (bdev_is_partition(part) && !bdev_nr_sectors(part))
continue;
if (!kobject_get_unless_zero(&part->bd_device.kobj))
continue;
rcu_read_unlock();
kobject_uevent(bdev_kobj(part), action);
put_device(&part->bd_device);
rcu_read_lock();
}
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(disk_uevent);
int disk_scan_partitions(struct gendisk *disk, fmode_t mode, void *owner)
{
struct block_device *bdev;
if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN))
return -EINVAL;
if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
return -EINVAL;
if (disk->open_partitions)
return -EBUSY;
/* Someone else has bdev exclusively open? */
if (disk->part0->bd_holder && disk->part0->bd_holder != owner)
return -EBUSY;
set_bit(GD_NEED_PART_SCAN, &disk->state);
bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
blkdev_put(bdev, mode);
return 0;
}
/**
* 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
*
* This function registers the partitioning information in @disk
* with the kernel.
*/
int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
const struct attribute_group **groups)
{
struct device *ddev = disk_to_dev(disk);
int ret;
/* Only makes sense for bio-based to set ->poll_bio */
if (queue_is_mq(disk->queue) && disk->fops->poll_bio)
return -EINVAL;
/*
* 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.
*/
elevator_init_mq(disk->queue);
/*
* If the driver provides an explicit major number it also must provide
* the number of minors numbers supported, and those will be used to
* setup the gendisk.
* Otherwise just allocate the device numbers for both the whole device
* and all partitions from the extended dev_t space.
*/
ret = -EINVAL;
if (disk->major) {
if (WARN_ON(!disk->minors))
goto out_exit_elevator;
if (disk->minors > DISK_MAX_PARTS) {
pr_err("block: can't allocate more than %d partitions\n",
DISK_MAX_PARTS);
disk->minors = DISK_MAX_PARTS;
}
if (disk->first_minor + disk->minors > MINORMASK + 1)
goto out_exit_elevator;
} else {
if (WARN_ON(disk->minors))
goto out_exit_elevator;
ret = blk_alloc_ext_minor();
if (ret < 0)
goto out_exit_elevator;
disk->major = BLOCK_EXT_MAJOR;
disk->first_minor = ret;
}
/* delay uevents, until we scanned partition table */
dev_set_uevent_suppress(ddev, 1);
ddev->parent = parent;
ddev->groups = groups;
dev_set_name(ddev, "%s", disk->disk_name);
if (!(disk->flags & GENHD_FL_HIDDEN))
ddev->devt = MKDEV(disk->major, disk->first_minor);
ret = device_add(ddev);
if (ret)
goto out_free_ext_minor;
ret = disk_alloc_events(disk);
if (ret)
goto out_device_del;
if (!sysfs_deprecated) {
ret = sysfs_create_link(block_depr, &ddev->kobj,
kobject_name(&ddev->kobj));
if (ret)
goto out_device_del;
}
/*
* 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);
ret = blk_integrity_add(disk);
if (ret)
goto out_del_block_link;
disk->part0->bd_holder_dir =
kobject_create_and_add("holders", &ddev->kobj);
if (!disk->part0->bd_holder_dir) {
ret = -ENOMEM;
goto out_del_integrity;
}
disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
if (!disk->slave_dir) {
ret = -ENOMEM;
goto out_put_holder_dir;
}
ret = blk_register_queue(disk);
if (ret)
goto out_put_slave_dir;
if (!(disk->flags & GENHD_FL_HIDDEN)) {
ret = bdi_register(disk->bdi, "%u:%u",
disk->major, disk->first_minor);
if (ret)
goto out_unregister_queue;
bdi_set_owner(disk->bdi, ddev);
ret = sysfs_create_link(&ddev->kobj,
&disk->bdi->dev->kobj, "bdi");
if (ret)
goto out_unregister_bdi;
bdev_add(disk->part0, ddev->devt);
if (get_capacity(disk))
disk_scan_partitions(disk, FMODE_READ, NULL);
/*
* Announce the disk and partitions after all partitions are
* created. (for hidden disks uevents remain suppressed forever)
*/
dev_set_uevent_suppress(ddev, 0);
disk_uevent(disk, KOBJ_ADD);
} else {
/*
* Even if the block_device for a hidden gendisk is not
* registered, it needs to have a valid bd_dev so that the
* freeing of the dynamic major works.
*/
disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);
}
disk_update_readahead(disk);
disk_add_events(disk);
set_bit(GD_ADDED, &disk->state);
return 0;
out_unregister_bdi:
if (!(disk->flags & GENHD_FL_HIDDEN))
bdi_unregister(disk->bdi);
out_unregister_queue:
blk_unregister_queue(disk);
rq_qos_exit(disk->queue);
out_put_slave_dir:
kobject_put(disk->slave_dir);
disk->slave_dir = NULL;
out_put_holder_dir:
kobject_put(disk->part0->bd_holder_dir);
out_del_integrity:
blk_integrity_del(disk);
out_del_block_link:
if (!sysfs_deprecated)
sysfs_remove_link(block_depr, dev_name(ddev));
out_device_del:
device_del(ddev);
out_free_ext_minor:
if (disk->major == BLOCK_EXT_MAJOR)
blk_free_ext_minor(disk->first_minor);
out_exit_elevator:
if (disk->queue->elevator)
elevator_exit(disk->queue);
return ret;
}
EXPORT_SYMBOL(device_add_disk);
/**
* blk_mark_disk_dead - mark a disk as dead
* @disk: disk to mark as dead
*
* Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O
* to this disk.
*/
void blk_mark_disk_dead(struct gendisk *disk)
{
set_bit(GD_DEAD, &disk->state);
blk_queue_start_drain(disk->queue);
/*
* Stop buffered writers from dirtying pages that can't be written out.
*/
set_capacity_and_notify(disk, 0);
}
EXPORT_SYMBOL_GPL(blk_mark_disk_dead);
/**
* del_gendisk - remove the gendisk
* @disk: the struct gendisk to remove
*
* Removes the gendisk and all its associated resources. This deletes the
* partitions associated with the gendisk, and unregisters the associated
* request_queue.
*
* This is the counter to the respective __device_add_disk() call.
*
* The final removal of the struct gendisk happens when its refcount reaches 0
* with put_disk(), which should be called after del_gendisk(), if
* __device_add_disk() was used.
*
* Drivers exist which depend on the release of the gendisk to be synchronous,
* it should not be deferred.
*
* Context: can sleep
*/
void del_gendisk(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
might_sleep();
if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))
return;
blk_integrity_del(disk);
disk_del_events(disk);
mutex_lock(&disk->open_mutex);
remove_inode_hash(disk->part0->bd_inode);
blk_drop_partitions(disk);
mutex_unlock(&disk->open_mutex);
fsync_bdev(disk->part0);
__invalidate_device(disk->part0, true);
/*
* Fail any new I/O.
*/
set_bit(GD_DEAD, &disk->state);
if (test_bit(GD_OWNS_QUEUE, &disk->state))
blk_queue_flag_set(QUEUE_FLAG_DYING, q);
set_capacity(disk, 0);
/*
* Prevent new I/O from crossing bio_queue_enter().
*/
blk_queue_start_drain(q);
if (!(disk->flags & GENHD_FL_HIDDEN)) {
sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
/*
* Unregister bdi before releasing device numbers (as they can
* get reused and we'd get clashes in sysfs).
*/
bdi_unregister(disk->bdi);
}
blk_unregister_queue(disk);
kobject_put(disk->part0->bd_holder_dir);
kobject_put(disk->slave_dir);
disk->slave_dir = NULL;
part_stat_set_all(disk->part0, 0);
disk->part0->bd_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));
blk_mq_freeze_queue_wait(q);
blk_throtl_cancel_bios(disk);
blk_sync_queue(q);
blk_flush_integrity();
if (queue_is_mq(q))
blk_mq_cancel_work_sync(q);
blk_mq_quiesce_queue(q);
if (q->elevator) {
mutex_lock(&q->sysfs_lock);
elevator_exit(q);
mutex_unlock(&q->sysfs_lock);
}
rq_qos_exit(q);
blk_mq_unquiesce_queue(q);
/*
* If the disk does not own the queue, allow using passthrough requests
* again. Else leave the queue frozen to fail all I/O.
*/
if (!test_bit(GD_OWNS_QUEUE, &disk->state)) {
blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
__blk_mq_unfreeze_queue(q, true);
} else {
if (queue_is_mq(q))
blk_mq_exit_queue(q);
}
}
EXPORT_SYMBOL(del_gendisk);
/**
* invalidate_disk - invalidate the disk
* @disk: the struct gendisk to invalidate
*
* A helper to invalidates the disk. It will clean the disk's associated
* buffer/page caches and reset its internal states so that the disk
* can be reused by the drivers.
*
* Context: can sleep
*/
void invalidate_disk(struct gendisk *disk)
{
struct block_device *bdev = disk->part0;
invalidate_bdev(bdev);
bdev->bd_inode->i_mapping->wb_err = 0;
set_capacity(disk, 0);
}
EXPORT_SYMBOL(invalidate_disk);
/* 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);
}
#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
void blk_request_module(dev_t devt)
{
unsigned int major = MAJOR(devt);
struct blk_major_name **n;
mutex_lock(&major_names_lock);
for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {
if ((*n)->major == major && (*n)->probe) {
(*n)->probe(devt);
mutex_unlock(&major_names_lock);
return;
}
}
mutex_unlock(&major_names_lock);
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));
}
#endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */
/*
* 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 block_device *part;
char devt_buf[BDEVT_SIZE];
unsigned long idx;
/*
* Don't show empty devices or things that have been
* suppressed
*/
if (get_capacity(disk) == 0 || (disk->flags & GENHD_FL_HIDDEN))
continue;
/*
* Note, unlike /proc/partitions, I am showing the numbers in
* hex - the same format as the root= option takes.
*/
rcu_read_lock();
xa_for_each(&disk->part_tbl, idx, part) {
if (!bdev_nr_sectors(part))
continue;
printk("%s%s %10llu %pg %s",
bdev_is_partition(part) ? " " : "",
bdevt_str(part->bd_dev, devt_buf),
bdev_nr_sectors(part) >> 1, part,
part->bd_meta_info ?
part->bd_meta_info->uuid : "");
if (bdev_is_partition(part))
printk("\n");
else if (dev->parent && dev->parent->driver)
printk(" driver: %s\n",
dev->parent->driver->name);
else
printk(" (driver?)\n");
}
rcu_read_unlock();
}
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 block_device *part;
unsigned long idx;
if (!get_capacity(sgp) || (sgp->flags & GENHD_FL_HIDDEN))
return 0;
rcu_read_lock();
xa_for_each(&sgp->part_tbl, idx, part) {
if (!bdev_nr_sectors(part))
continue;
seq_printf(seqf, "%4d %7d %10llu %pg\n",
MAJOR(part->bd_dev), MINOR(part->bd_dev),
bdev_nr_sectors(part) >> 1, part);
}
rcu_read_unlock();
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 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;
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->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS);
}
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);
}
ssize_t part_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));
}
ssize_t part_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct block_device *bdev = dev_to_bdev(dev);
struct request_queue *q = bdev_get_queue(bdev);
struct disk_stats stat;
unsigned int inflight;
if (queue_is_mq(q))
inflight = blk_mq_in_flight(q, bdev);
else
inflight = part_in_flight(bdev);
if (inflight) {
part_stat_lock();
update_io_ticks(bdev, jiffies, true);
part_stat_unlock();
}
part_stat_read_all(bdev, &stat);
return sprintf(buf,
"%8lu %8lu %8llu %8u "
"%8lu %8lu %8llu %8u "
"%8u %8u %8u "
"%8lu %8lu %8llu %8u "
"%8lu %8u"
"\n",
stat.ios[STAT_READ],
stat.merges[STAT_READ],
(unsigned long long)stat.sectors[STAT_READ],
(unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC),
stat.ios[STAT_WRITE],
stat.merges[STAT_WRITE],
(unsigned long long)stat.sectors[STAT_WRITE],
(unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),
inflight,
jiffies_to_msecs(stat.io_ticks),
(unsigned int)div_u64(stat.nsecs[STAT_READ] +
stat.nsecs[STAT_WRITE] +
stat.nsecs[STAT_DISCARD] +
stat.nsecs[STAT_FLUSH],
NSEC_PER_MSEC),
stat.ios[STAT_DISCARD],
stat.merges[STAT_DISCARD],
(unsigned long long)stat.sectors[STAT_DISCARD],
(unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC),
stat.ios[STAT_FLUSH],
(unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC));
}
ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct block_device *bdev = dev_to_bdev(dev);
struct request_queue *q = bdev_get_queue(bdev);
unsigned int inflight[2];
if (queue_is_mq(q))
blk_mq_in_flight_rw(q, bdev, inflight);
else
part_in_flight_rw(bdev, inflight);
return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
}
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", bdev_alignment_offset(disk->part0));
}
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", bdev_alignment_offset(disk->part0));
}
static ssize_t diskseq_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
return sprintf(buf, "%llu\n", disk->diskseq);
}
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);
static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
ssize_t part_fail_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail);
}
ssize_t part_fail_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int i;
if (count > 0 && sscanf(buf, "%d", &i) > 0)
dev_to_bdev(dev)->bd_make_it_fail = i;
return count;
}
static struct device_attribute dev_attr_fail =
__ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
#endif /* CONFIG_FAIL_MAKE_REQUEST */
#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,
&dev_attr_events.attr,
&dev_attr_events_async.attr,
&dev_attr_events_poll_msecs.attr,
&dev_attr_diskseq.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,
#ifdef CONFIG_BLK_DEV_IO_TRACE
&blk_trace_attr_group,
#endif
NULL
};
/**
* disk_release - releases all allocated resources of the gendisk
* @dev: the device representing this disk
*
* This function releases all allocated resources of the gendisk.
*
* Drivers which used __device_add_disk() have a gendisk with a request_queue
* assigned. Since the request_queue sits on top of the gendisk for these
* drivers we also call blk_put_queue() for them, and we expect the
* request_queue refcount to reach 0 at this point, and so the request_queue
* will also be freed prior to the disk.
*
* Context: can sleep
*/
static void disk_release(struct device *dev)
{
struct gendisk *disk = dev_to_disk(dev);
might_sleep();
WARN_ON_ONCE(disk_live(disk));
/*
* To undo the all initialization from blk_mq_init_allocated_queue in
* case of a probe failure where add_disk is never called we have to
* call blk_mq_exit_queue here. We can't do this for the more common
* teardown case (yet) as the tagset can be gone by the time the disk
* is released once it was added.
*/
if (queue_is_mq(disk->queue) &&
test_bit(GD_OWNS_QUEUE, &disk->state) &&
!test_bit(GD_ADDED, &disk->state))
blk_mq_exit_queue(disk->queue);
blkcg_exit_disk(disk);
bioset_exit(&disk->bio_split);
disk_release_events(disk);
kfree(disk->random);
disk_free_zone_bitmaps(disk);
xa_destroy(&disk->part_tbl);
disk->queue->disk = NULL;
blk_put_queue(disk->queue);
if (test_bit(GD_ADDED, &disk->state) && disk->fops->free_disk)
disk->fops->free_disk(disk);
iput(disk->part0->bd_inode); /* frees the disk */
}
static int block_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
const struct gendisk *disk = dev_to_disk(dev);
return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq);
}
struct class block_class = {
.name = "block",
.dev_uevent = block_uevent,
};
const 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 block_device *hd;
unsigned int inflight;
struct disk_stats stat;
unsigned long idx;
/*
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");
*/
rcu_read_lock();
xa_for_each(&gp->part_tbl, idx, hd) {
if (bdev_is_partition(hd) && !bdev_nr_sectors(hd))
continue;
if (queue_is_mq(gp->queue))
inflight = blk_mq_in_flight(gp->queue, hd);
else
inflight = part_in_flight(hd);
if (inflight) {
part_stat_lock();
update_io_ticks(hd, jiffies, true);
part_stat_unlock();
}
part_stat_read_all(hd, &stat);
seq_printf(seqf, "%4d %7d %pg "
"%lu %lu %lu %u "
"%lu %lu %lu %u "
"%u %u %u "
"%lu %lu %lu %u "
"%lu %u"
"\n",
MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd,
stat.ios[STAT_READ],
stat.merges[STAT_READ],
stat.sectors[STAT_READ],
(unsigned int)div_u64(stat.nsecs[STAT_READ],
NSEC_PER_MSEC),
stat.ios[STAT_WRITE],
stat.merges[STAT_WRITE],
stat.sectors[STAT_WRITE],
(unsigned int)div_u64(stat.nsecs[STAT_WRITE],
NSEC_PER_MSEC),
inflight,
jiffies_to_msecs(stat.io_ticks),
(unsigned int)div_u64(stat.nsecs[STAT_READ] +
stat.nsecs[STAT_WRITE] +
stat.nsecs[STAT_DISCARD] +
stat.nsecs[STAT_FLUSH],
NSEC_PER_MSEC),
stat.ios[STAT_DISCARD],
stat.merges[STAT_DISCARD],
stat.sectors[STAT_DISCARD],
(unsigned int)div_u64(stat.nsecs[STAT_DISCARD],
NSEC_PER_MSEC),
stat.ios[STAT_FLUSH],
(unsigned int)div_u64(stat.nsecs[STAT_FLUSH],
NSEC_PER_MSEC)
);
}
rcu_read_unlock();
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 part_devt(struct gendisk *disk, u8 partno)
{
struct block_device *part;
dev_t devt = 0;
rcu_read_lock();
part = xa_load(&disk->part_tbl, partno);
if (part)
devt = part->bd_dev;
rcu_read_unlock();
return devt;
}
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);
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);
} else {
devt = part_devt(disk, partno);
if (devt)
break;
}
}
class_dev_iter_exit(&iter);
return devt;
}
struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
struct lock_class_key *lkclass)
{
struct gendisk *disk;
disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
if (!disk)
return NULL;
if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0))
goto out_free_disk;
disk->bdi = bdi_alloc(node_id);
if (!disk->bdi)
goto out_free_bioset;
/* bdev_alloc() might need the queue, set before the first call */
disk->queue = q;
disk->part0 = bdev_alloc(disk, 0);
if (!disk->part0)
goto out_free_bdi;
disk->node_id = node_id;
mutex_init(&disk->open_mutex);
xa_init(&disk->part_tbl);
if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
goto out_destroy_part_tbl;
if (blkcg_init_disk(disk))
goto out_erase_part0;
rand_initialize_disk(disk);
disk_to_dev(disk)->class = &block_class;
disk_to_dev(disk)->type = &disk_type;
device_initialize(disk_to_dev(disk));
inc_diskseq(disk);
q->disk = disk;
lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0);
#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
INIT_LIST_HEAD(&disk->slave_bdevs);
#endif
return disk;
out_erase_part0:
xa_erase(&disk->part_tbl, 0);
out_destroy_part_tbl:
xa_destroy(&disk->part_tbl);
disk->part0->bd_disk = NULL;
iput(disk->part0->bd_inode);
out_free_bdi:
bdi_put(disk->bdi);
out_free_bioset:
bioset_exit(&disk->bio_split);
out_free_disk:
kfree(disk);
return NULL;
}
struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
{
struct request_queue *q;
struct gendisk *disk;
q = blk_alloc_queue(node);
if (!q)
return NULL;
disk = __alloc_disk_node(q, node, lkclass);
if (!disk) {
blk_put_queue(q);
return NULL;
}
set_bit(GD_OWNS_QUEUE, &disk->state);
return disk;
}
EXPORT_SYMBOL(__blk_alloc_disk);
/**
* put_disk - decrements the gendisk refcount
* @disk: the struct gendisk to decrement the refcount for
*
* This decrements the refcount for the struct gendisk. When this reaches 0
* we'll have disk_release() called.
*
* Note: for blk-mq disk put_disk must be called before freeing the tag_set
* when handling probe errors (that is before add_disk() is called).
*
* Context: Any context, but the last reference must not be dropped from
* atomic context.
*/
void put_disk(struct gendisk *disk)
{
if (disk)
put_device(disk_to_dev(disk));
}
EXPORT_SYMBOL(put_disk);
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);
}
/**
* set_disk_ro - set a gendisk read-only
* @disk: gendisk to operate on
* @read_only: %true to set the disk read-only, %false set the disk read/write
*
* This function is used to indicate whether a given disk device should have its
* read-only flag set. set_disk_ro() is typically used by device drivers to
* indicate whether the underlying physical device is write-protected.
*/
void set_disk_ro(struct gendisk *disk, bool read_only)
{
if (read_only) {
if (test_and_set_bit(GD_READ_ONLY, &disk->state))
return;
} else {
if (!test_and_clear_bit(GD_READ_ONLY, &disk->state))
return;
}
set_disk_ro_uevent(disk, read_only);
}
EXPORT_SYMBOL(set_disk_ro);
void inc_diskseq(struct gendisk *disk)
{
disk->diskseq = atomic64_inc_return(&diskseq);
}