kernel-ark/block/genhd.c
Linus Torvalds 033d9959ed Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue changes from Tejun Heo:
 "This is workqueue updates for v3.7-rc1.  A lot of activities this
  round including considerable API and behavior cleanups.

   * delayed_work combines a timer and a work item.  The handling of the
     timer part has always been a bit clunky leading to confusing
     cancelation API with weird corner-case behaviors.  delayed_work is
     updated to use new IRQ safe timer and cancelation now works as
     expected.

   * Another deficiency of delayed_work was lack of the counterpart of
     mod_timer() which led to cancel+queue combinations or open-coded
     timer+work usages.  mod_delayed_work[_on]() are added.

     These two delayed_work changes make delayed_work provide interface
     and behave like timer which is executed with process context.

   * A work item could be executed concurrently on multiple CPUs, which
     is rather unintuitive and made flush_work() behavior confusing and
     half-broken under certain circumstances.  This problem doesn't
     exist for non-reentrant workqueues.  While non-reentrancy check
     isn't free, the overhead is incurred only when a work item bounces
     across different CPUs and even in simulated pathological scenario
     the overhead isn't too high.

     All workqueues are made non-reentrant.  This removes the
     distinction between flush_[delayed_]work() and
     flush_[delayed_]_work_sync().  The former is now as strong as the
     latter and the specified work item is guaranteed to have finished
     execution of any previous queueing on return.

   * In addition to the various bug fixes, Lai redid and simplified CPU
     hotplug handling significantly.

   * Joonsoo introduced system_highpri_wq and used it during CPU
     hotplug.

  There are two merge commits - one to pull in IRQ safe timer from
  tip/timers/core and the other to pull in CPU hotplug fixes from
  wq/for-3.6-fixes as Lai's hotplug restructuring depended on them."

Fixed a number of trivial conflicts, but the more interesting conflicts
were silent ones where the deprecated interfaces had been used by new
code in the merge window, and thus didn't cause any real data conflicts.

Tejun pointed out a few of them, I fixed a couple more.

* 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits)
  workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending()
  workqueue: use cwq_set_max_active() helper for workqueue_set_max_active()
  workqueue: introduce cwq_set_max_active() helper for thaw_workqueues()
  workqueue: remove @delayed from cwq_dec_nr_in_flight()
  workqueue: fix possible stall on try_to_grab_pending() of a delayed work item
  workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback()
  workqueue: use __cpuinit instead of __devinit for cpu callbacks
  workqueue: rename manager_mutex to assoc_mutex
  workqueue: WORKER_REBIND is no longer necessary for idle rebinding
  workqueue: WORKER_REBIND is no longer necessary for busy rebinding
  workqueue: reimplement idle worker rebinding
  workqueue: deprecate __cancel_delayed_work()
  workqueue: reimplement cancel_delayed_work() using try_to_grab_pending()
  workqueue: use mod_delayed_work() instead of __cancel + queue
  workqueue: use irqsafe timer for delayed_work
  workqueue: clean up delayed_work initializers and add missing one
  workqueue: make deferrable delayed_work initializer names consistent
  workqueue: cosmetic whitespace updates for macro definitions
  workqueue: deprecate system_nrt[_freezable]_wq
  workqueue: deprecate flush[_delayed]_work_sync()
  ...
2012-10-02 09:54:49 -07:00

1816 lines
43 KiB
C

/*
* gendisk handling
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/kdev_t.h>
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/kobj_map.h>
#include <linux/mutex.h>
#include <linux/idr.h>
#include <linux/log2.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 MAX_EXT_DEVT (1 << MINORBITS)
/* For extended devt allocation. ext_devt_mutex prevents look up
* results from going away underneath its user.
*/
static DEFINE_MUTEX(ext_devt_mutex);
static DEFINE_IDR(ext_devt_idr);
static struct device_type disk_type;
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);
/**
* disk_get_part - get partition
* @disk: disk to look partition from
* @partno: partition number
*
* Look for partition @partno from @disk. If found, increment
* reference count and return it.
*
* CONTEXT:
* Don't care.
*
* RETURNS:
* Pointer to the found partition on success, NULL if not found.
*/
struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
{
struct hd_struct *part = NULL;
struct disk_part_tbl *ptbl;
if (unlikely(partno < 0))
return NULL;
rcu_read_lock();
ptbl = rcu_dereference(disk->part_tbl);
if (likely(partno < ptbl->len)) {
part = rcu_dereference(ptbl->part[partno]);
if (part)
get_device(part_to_dev(part));
}
rcu_read_unlock();
return part;
}
EXPORT_SYMBOL_GPL(disk_get_part);
/**
* disk_part_iter_init - initialize partition iterator
* @piter: iterator to initialize
* @disk: disk to iterate over
* @flags: DISK_PITER_* flags
*
* Initialize @piter so that it iterates over partitions of @disk.
*
* CONTEXT:
* Don't care.
*/
void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
unsigned int flags)
{
struct disk_part_tbl *ptbl;
rcu_read_lock();
ptbl = rcu_dereference(disk->part_tbl);
piter->disk = disk;
piter->part = NULL;
if (flags & DISK_PITER_REVERSE)
piter->idx = ptbl->len - 1;
else if (flags & (DISK_PITER_INCL_PART0 | 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.
*
*/
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;
if (offset < BLKDEV_MAJOR_HASH_SIZE) {
mutex_lock(&block_class_lock);
for (dp = major_names[offset]; dp; dp = dp->next)
seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
mutex_unlock(&block_class_lock);
}
}
#endif /* CONFIG_PROC_FS */
/**
* register_blkdev - register a new block device
*
* @major: the requested major device number [1..255]. 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..255] 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..255] or a negative error code otherwise
*/
int register_blkdev(unsigned int major, const char *name)
{
struct blk_major_name **n, *p;
int index, ret = 0;
mutex_lock(&block_class_lock);
/* temporary */
if (major == 0) {
for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
if (major_names[index] == NULL)
break;
}
if (index == 0) {
printk("register_blkdev: failed to get major for %s\n",
name);
ret = -EBUSY;
goto out;
}
major = index;
ret = major;
}
p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
if (p == NULL) {
ret = -ENOMEM;
goto out;
}
p->major = major;
strlcpy(p->name, name, sizeof(p->name));
p->next = NULL;
index = major_to_index(major);
for (n = &major_names[index]; *n; n = &(*n)->next) {
if ((*n)->major == major)
break;
}
if (!*n)
*n = p;
else
ret = -EBUSY;
if (ret < 0) {
printk("register_blkdev: cannot get major %d for %s\n",
major, name);
kfree(p);
}
out:
mutex_unlock(&block_class_lock);
return ret;
}
EXPORT_SYMBOL(register_blkdev);
void unregister_blkdev(unsigned int major, const char *name)
{
struct blk_major_name **n;
struct blk_major_name *p = NULL;
int index = major_to_index(major);
mutex_lock(&block_class_lock);
for (n = &major_names[index]; *n; n = &(*n)->next)
if ((*n)->major == major)
break;
if (!*n || strcmp((*n)->name, name)) {
WARN_ON(1);
} else {
p = *n;
*n = p->next;
}
mutex_unlock(&block_class_lock);
kfree(p);
}
EXPORT_SYMBOL(unregister_blkdev);
static struct kobj_map *bdev_map;
/**
* blk_mangle_minor - scatter minor numbers apart
* @minor: minor number to mangle
*
* Scatter consecutively allocated @minor number apart if MANGLE_DEVT
* is enabled. Mangling twice gives the original value.
*
* RETURNS:
* Mangled value.
*
* CONTEXT:
* Don't care.
*/
static int blk_mangle_minor(int minor)
{
#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
int i;
for (i = 0; i < MINORBITS / 2; i++) {
int low = minor & (1 << i);
int high = minor & (1 << (MINORBITS - 1 - i));
int distance = MINORBITS - 1 - 2 * i;
minor ^= low | high; /* clear both bits */
low <<= distance; /* swap the positions */
high >>= distance;
minor |= low | high; /* and set */
}
#endif
return minor;
}
/**
* blk_alloc_devt - allocate a dev_t for a partition
* @part: partition to allocate dev_t for
* @devt: out parameter for resulting dev_t
*
* Allocate a dev_t for block device.
*
* RETURNS:
* 0 on success, allocated dev_t is returned in *@devt. -errno on
* failure.
*
* CONTEXT:
* Might sleep.
*/
int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
{
struct gendisk *disk = part_to_disk(part);
int idx, rc;
/* in consecutive minor range? */
if (part->partno < disk->minors) {
*devt = MKDEV(disk->major, disk->first_minor + part->partno);
return 0;
}
/* allocate ext devt */
do {
if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL))
return -ENOMEM;
rc = idr_get_new(&ext_devt_idr, part, &idx);
} while (rc == -EAGAIN);
if (rc)
return rc;
if (idx > MAX_EXT_DEVT) {
idr_remove(&ext_devt_idr, idx);
return -EBUSY;
}
*devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
return 0;
}
/**
* blk_free_devt - free a dev_t
* @devt: dev_t to free
*
* Free @devt which was allocated using blk_alloc_devt().
*
* CONTEXT:
* Might sleep.
*/
void blk_free_devt(dev_t devt)
{
might_sleep();
if (devt == MKDEV(0, 0))
return;
if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
mutex_lock(&ext_devt_mutex);
idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
mutex_unlock(&ext_devt_mutex);
}
}
static char *bdevt_str(dev_t devt, char *buf)
{
if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
char tbuf[BDEVT_SIZE];
snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
} else
snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
return buf;
}
/*
* Register device numbers dev..(dev+range-1)
* range must be nonzero
* The hash chain is sorted on range, so that subranges can override.
*/
void blk_register_region(dev_t devt, unsigned long range, struct module *module,
struct kobject *(*probe)(dev_t, int *, void *),
int (*lock)(dev_t, void *), void *data)
{
kobj_map(bdev_map, devt, range, module, probe, lock, data);
}
EXPORT_SYMBOL(blk_register_region);
void blk_unregister_region(dev_t devt, unsigned long range)
{
kobj_unmap(bdev_map, devt, range);
}
EXPORT_SYMBOL(blk_unregister_region);
static struct kobject *exact_match(dev_t devt, int *partno, void *data)
{
struct gendisk *p = data;
return &disk_to_dev(p)->kobj;
}
static int exact_lock(dev_t devt, void *data)
{
struct gendisk *p = data;
if (!get_disk(p))
return -1;
return 0;
}
static void register_disk(struct gendisk *disk)
{
struct device *ddev = disk_to_dev(disk);
struct block_device *bdev;
struct disk_part_iter piter;
struct hd_struct *part;
int err;
ddev->parent = disk->driverfs_dev;
dev_set_name(ddev, disk->disk_name);
/* delay uevents, until we scanned partition table */
dev_set_uevent_suppress(ddev, 1);
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;
}
}
disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
/* 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);
}
/**
* add_disk - add partitioning information to kernel list
* @disk: per-device partitioning information
*
* This function registers the partitioning information in @disk
* with the kernel.
*
* FIXME: error handling
*/
void add_disk(struct gendisk *disk)
{
struct backing_dev_info *bdi;
dev_t devt;
int retval;
/* minors == 0 indicates to use ext devt from part0 and should
* be accompanied with EXT_DEVT flag. Make sure all
* parameters make sense.
*/
WARN_ON(disk->minors && !(disk->major || disk->first_minor));
WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT));
disk->flags |= GENHD_FL_UP;
retval = blk_alloc_devt(&disk->part0, &devt);
if (retval) {
WARN_ON(1);
return;
}
disk_to_dev(disk)->devt = devt;
/* ->major and ->first_minor aren't supposed to be
* dereferenced from here on, but set them just in case.
*/
disk->major = MAJOR(devt);
disk->first_minor = MINOR(devt);
disk_alloc_events(disk);
/* Register BDI before referencing it from bdev */
bdi = &disk->queue->backing_dev_info;
bdi_register_dev(bdi, disk_devt(disk));
blk_register_region(disk_devt(disk), disk->minors, NULL,
exact_match, exact_lock, disk);
register_disk(disk);
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));
retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
"bdi");
WARN_ON(retval);
disk_add_events(disk);
}
EXPORT_SYMBOL(add_disk);
void del_gendisk(struct gendisk *disk)
{
struct disk_part_iter piter;
struct hd_struct *part;
disk_del_events(disk);
/* 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);
delete_partition(disk, part->partno);
}
disk_part_iter_exit(&piter);
invalidate_partition(disk, 0);
blk_free_devt(disk_to_dev(disk)->devt);
set_capacity(disk, 0);
disk->flags &= ~GENHD_FL_UP;
sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
bdi_unregister(&disk->queue->backing_dev_info);
blk_unregister_queue(disk);
blk_unregister_region(disk_devt(disk), disk->minors);
part_stat_set_all(&disk->part0, 0);
disk->part0.stamp = 0;
kobject_put(disk->part0.holder_dir);
kobject_put(disk->slave_dir);
disk->driverfs_dev = NULL;
if (!sysfs_deprecated)
sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
device_del(disk_to_dev(disk));
}
EXPORT_SYMBOL(del_gendisk);
/**
* get_gendisk - get partitioning information for a given device
* @devt: device to get partitioning information for
* @partno: returned partition index
*
* This function gets the structure containing partitioning
* information for the given device @devt.
*/
struct gendisk *get_gendisk(dev_t devt, int *partno)
{
struct gendisk *disk = NULL;
if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
struct kobject *kobj;
kobj = kobj_lookup(bdev_map, devt, partno);
if (kobj)
disk = dev_to_disk(kobj_to_dev(kobj));
} else {
struct hd_struct *part;
mutex_lock(&ext_devt_mutex);
part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
if (part && get_disk(part_to_disk(part))) {
*partno = part->partno;
disk = part_to_disk(part);
}
mutex_unlock(&ext_devt_mutex);
}
return disk;
}
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];
char uuid_buf[PARTITION_META_INFO_UUIDLTH * 2 + 5];
/*
* 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;
uuid_buf[0] = '\0';
if (part->info)
snprintf(uuid_buf, sizeof(uuid_buf), "%pU",
part->info->uuid);
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),
uuid_buf);
if (is_part0) {
if (disk->driverfs_dev != NULL &&
disk->driverfs_dev->driver != NULL)
printk(" driver: %s\n",
disk->driverfs_dev->driver->name);
else
printk(" (driver?)\n");
} else
printk("\n");
}
disk_part_iter_exit(&piter);
}
class_dev_iter_exit(&iter);
}
#ifdef CONFIG_PROC_FS
/* iterator */
static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
{
loff_t skip = *pos;
struct class_dev_iter *iter;
struct device *dev;
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return ERR_PTR(-ENOMEM);
seqf->private = iter;
class_dev_iter_init(iter, &block_class, NULL, &disk_type);
do {
dev = class_dev_iter_next(iter);
if (!dev)
return NULL;
} while (skip--);
return dev_to_disk(dev);
}
static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
{
struct device *dev;
(*pos)++;
dev = class_dev_iter_next(seqf->private);
if (dev)
return dev_to_disk(dev);
return NULL;
}
static void disk_seqf_stop(struct seq_file *seqf, void *v)
{
struct class_dev_iter *iter = seqf->private;
/* stop is called even after start failed :-( */
if (iter) {
class_dev_iter_exit(iter);
kfree(iter);
}
}
static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
{
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
};
static int partitions_open(struct inode *inode, struct file *file)
{
return seq_open(file, &partitions_op);
}
static const struct file_operations proc_partitions_operations = {
.open = partitions_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif
static struct kobject *base_probe(dev_t devt, int *partno, void *data)
{
if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
/* Make old-style 2.4 aliases work */
request_module("block-major-%d", MAJOR(devt));
return NULL;
}
static int __init genhd_device_init(void)
{
int error;
block_class.dev_kobj = sysfs_dev_block_kobj;
error = class_register(&block_class);
if (unlikely(error))
return error;
bdev_map = kobj_map_init(base_probe, &block_class_lock);
blk_dev_init();
register_blkdev(BLOCK_EXT_MAJOR, "blkext");
/* 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_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, S_IRUGO, disk_range_show, NULL);
static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL);
static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL);
static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show,
NULL);
static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
static struct device_attribute dev_attr_fail =
__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
#endif
#ifdef CONFIG_FAIL_IO_TIMEOUT
static struct device_attribute dev_attr_fail_timeout =
__ATTR(io-timeout-fail, S_IRUGO|S_IWUSR, part_timeout_show,
part_timeout_store);
#endif
static struct attribute *disk_attrs[] = {
&dev_attr_range.attr,
&dev_attr_ext_range.attr,
&dev_attr_removable.attr,
&dev_attr_ro.attr,
&dev_attr_size.attr,
&dev_attr_alignment_offset.attr,
&dev_attr_discard_alignment.attr,
&dev_attr_capability.attr,
&dev_attr_stat.attr,
&dev_attr_inflight.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&dev_attr_fail.attr,
#endif
#ifdef CONFIG_FAIL_IO_TIMEOUT
&dev_attr_fail_timeout.attr,
#endif
NULL
};
static struct attribute_group disk_attr_group = {
.attrs = disk_attrs,
};
static 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_mutx locked.
*/
static void disk_replace_part_tbl(struct gendisk *disk,
struct disk_part_tbl *new_ptbl)
{
struct disk_part_tbl *old_ptbl = disk->part_tbl;
rcu_assign_pointer(disk->part_tbl, new_ptbl);
if (old_ptbl) {
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, might sleep.
*
* RETURNS:
* 0 on success, -errno on failure.
*/
int disk_expand_part_tbl(struct gendisk *disk, int partno)
{
struct disk_part_tbl *old_ptbl = disk->part_tbl;
struct disk_part_tbl *new_ptbl;
int len = old_ptbl ? old_ptbl->len : 0;
int target = partno + 1;
size_t size;
int i;
/* disk_max_parts() is zero during initialization, ignore if so */
if (disk_max_parts(disk) && target > disk_max_parts(disk))
return -EINVAL;
if (target <= len)
return 0;
size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]);
new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id);
if (!new_ptbl)
return -ENOMEM;
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);
disk_release_events(disk);
kfree(disk->random);
disk_replace_part_tbl(disk, NULL);
free_part_stats(&disk->part0);
free_part_info(&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)
{
struct gendisk *disk = dev_to_disk(dev);
if (disk->devnode)
return disk->devnode(disk, mode);
return NULL;
}
static 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];
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(cpu, hd);
part_stat_unlock();
seq_printf(seqf, "%4d %7d %s %lu %lu %lu "
"%u %lu %lu %lu %u %u %u %u\n",
MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
disk_name(gp, hd->partno, buf),
part_stat_read(hd, ios[READ]),
part_stat_read(hd, merges[READ]),
part_stat_read(hd, sectors[READ]),
jiffies_to_msecs(part_stat_read(hd, ticks[READ])),
part_stat_read(hd, ios[WRITE]),
part_stat_read(hd, merges[WRITE]),
part_stat_read(hd, sectors[WRITE]),
jiffies_to_msecs(part_stat_read(hd, ticks[WRITE])),
part_in_flight(hd),
jiffies_to_msecs(part_stat_read(hd, io_ticks)),
jiffies_to_msecs(part_stat_read(hd, time_in_queue))
);
}
disk_part_iter_exit(&piter);
return 0;
}
static const struct seq_operations diskstats_op = {
.start = disk_seqf_start,
.next = disk_seqf_next,
.stop = disk_seqf_stop,
.show = diskstats_show
};
static int diskstats_open(struct inode *inode, struct file *file)
{
return seq_open(file, &diskstats_op);
}
static const struct file_operations proc_diskstats_operations = {
.open = diskstats_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init proc_genhd_init(void)
{
proc_create("diskstats", 0, NULL, &proc_diskstats_operations);
proc_create("partitions", 0, NULL, &proc_partitions_operations);
return 0;
}
module_init(proc_genhd_init);
#endif /* CONFIG_PROC_FS */
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(int minors)
{
return alloc_disk_node(minors, -1);
}
EXPORT_SYMBOL(alloc_disk);
struct gendisk *alloc_disk_node(int minors, int node_id)
{
struct gendisk *disk;
disk = kmalloc_node(sizeof(struct gendisk),
GFP_KERNEL | __GFP_ZERO, node_id);
if (disk) {
if (!init_part_stats(&disk->part0)) {
kfree(disk);
return NULL;
}
disk->node_id = node_id;
if (disk_expand_part_tbl(disk, 0)) {
free_part_stats(&disk->part0);
kfree(disk);
return NULL;
}
disk->part_tbl->part[0] = &disk->part0;
/*
* 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);
hd_ref_init(&disk->part0);
disk->minors = minors;
rand_initialize_disk(disk);
disk_to_dev(disk)->class = &block_class;
disk_to_dev(disk)->type = &disk_type;
device_initialize(disk_to_dev(disk));
}
return disk;
}
EXPORT_SYMBOL(alloc_disk_node);
struct kobject *get_disk(struct gendisk *disk)
{
struct module *owner;
struct kobject *kobj;
if (!disk->fops)
return NULL;
owner = disk->fops->owner;
if (owner && !try_module_get(owner))
return NULL;
kobj = kobject_get(&disk_to_dev(disk)->kobj);
if (kobj == NULL) {
module_put(owner);
return NULL;
}
return kobj;
}
EXPORT_SYMBOL(get_disk);
void put_disk(struct gendisk *disk)
{
if (disk)
kobject_put(&disk_to_dev(disk)->kobj);
}
EXPORT_SYMBOL(put_disk);
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 = 0;
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;
/*
* Not exactly a latency critical operation, set poll timer
* slack to 25% and kick event check.
*/
intv = disk_events_poll_jiffies(disk);
set_timer_slack(&ev->dwork.timer, intv / 4);
if (check_now)
queue_delayed_work(system_freezable_wq, &ev->dwork, 0);
else if (intv)
queue_delayed_work(system_freezable_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_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 clearted
*
* 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;
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;
}
/* tell the workfn about the events being cleared */
spin_lock_irq(&ev->lock);
ev->clearing |= mask;
spin_unlock_irq(&ev->lock);
/* uncondtionally schedule event check and wait for it to finish */
disk_block_events(disk);
queue_delayed_work(system_freezable_wq, &ev->dwork, 0);
flush_delayed_work(&ev->dwork);
__disk_unblock_events(disk, false);
/* then, fetch and clear pending events */
spin_lock_irq(&ev->lock);
WARN_ON_ONCE(ev->clearing & mask); /* cleared by workfn */
pending = ev->pending & mask;
ev->pending &= ~mask;
spin_unlock_irq(&ev->lock);
return pending;
}
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);
struct gendisk *disk = ev->disk;
char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
unsigned int clearing = ev->clearing;
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;
ev->clearing &= ~clearing;
intv = disk_events_poll_jiffies(disk);
if (!ev->block && intv)
queue_delayed_work(system_freezable_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, S_IRUGO, disk_events_show, NULL);
static const DEVICE_ATTR(events_async, S_IRUGO, disk_events_async_show, NULL);
static const DEVICE_ATTR(events_poll_msecs, S_IRUGO|S_IWUSR,
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);
}