linux/block/blk-sysfs.c
Christoph Hellwig 99d055b4fd block: remove per-disk debugfs files in blk_unregister_queue
The block debugfs files are created in blk_register_queue, which is
called by add_disk and use a naming scheme based on the disk_name.
After del_gendisk returns that name can be reused and thus we must not
leave these debugfs files around, otherwise the kernel is unhappy
and spews messages like:

	Directory XXXXX with parent 'block' already present!

and the newly created devices will not have working debugfs files.

Move the unregistration to blk_unregister_queue instead (which matches
the sysfs unregistration) to make sure the debugfs life time rules match
those of the disk name.

As part of the move also make sure the whole debugfs unregistration is
inside a single debugfs_mutex critical section.

Note that this breaks blktests block/002, which checks that the debugfs
directory has not been removed while blktests is running, but that
particular check should simply be removed from the test case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220614074827.458955-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-06-17 07:31:05 -06:00

954 lines
24 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Functions related to sysfs handling
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/blktrace_api.h>
#include <linux/blk-mq.h>
#include <linux/debugfs.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-debugfs.h"
#include "blk-mq-sched.h"
#include "blk-wbt.h"
#include "blk-cgroup.h"
#include "blk-throttle.h"
struct queue_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct request_queue *, char *);
ssize_t (*store)(struct request_queue *, const char *, size_t);
};
static ssize_t
queue_var_show(unsigned long var, char *page)
{
return sprintf(page, "%lu\n", var);
}
static ssize_t
queue_var_store(unsigned long *var, const char *page, size_t count)
{
int err;
unsigned long v;
err = kstrtoul(page, 10, &v);
if (err || v > UINT_MAX)
return -EINVAL;
*var = v;
return count;
}
static ssize_t queue_var_store64(s64 *var, const char *page)
{
int err;
s64 v;
err = kstrtos64(page, 10, &v);
if (err < 0)
return err;
*var = v;
return 0;
}
static ssize_t queue_requests_show(struct request_queue *q, char *page)
{
return queue_var_show(q->nr_requests, page);
}
static ssize_t
queue_requests_store(struct request_queue *q, const char *page, size_t count)
{
unsigned long nr;
int ret, err;
if (!queue_is_mq(q))
return -EINVAL;
ret = queue_var_store(&nr, page, count);
if (ret < 0)
return ret;
if (nr < BLKDEV_MIN_RQ)
nr = BLKDEV_MIN_RQ;
err = blk_mq_update_nr_requests(q, nr);
if (err)
return err;
return ret;
}
static ssize_t queue_ra_show(struct request_queue *q, char *page)
{
unsigned long ra_kb;
if (!q->disk)
return -EINVAL;
ra_kb = q->disk->bdi->ra_pages << (PAGE_SHIFT - 10);
return queue_var_show(ra_kb, page);
}
static ssize_t
queue_ra_store(struct request_queue *q, const char *page, size_t count)
{
unsigned long ra_kb;
ssize_t ret;
if (!q->disk)
return -EINVAL;
ret = queue_var_store(&ra_kb, page, count);
if (ret < 0)
return ret;
q->disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
return ret;
}
static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
{
int max_sectors_kb = queue_max_sectors(q) >> 1;
return queue_var_show(max_sectors_kb, page);
}
static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_max_segments(q), page);
}
static ssize_t queue_max_discard_segments_show(struct request_queue *q,
char *page)
{
return queue_var_show(queue_max_discard_segments(q), page);
}
static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.max_integrity_segments, page);
}
static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_max_segment_size(q), page);
}
static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_logical_block_size(q), page);
}
static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_physical_block_size(q), page);
}
static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.chunk_sectors, page);
}
static ssize_t queue_io_min_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_io_min(q), page);
}
static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_io_opt(q), page);
}
static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.discard_granularity, page);
}
static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
{
return sprintf(page, "%llu\n",
(unsigned long long)q->limits.max_hw_discard_sectors << 9);
}
static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
{
return sprintf(page, "%llu\n",
(unsigned long long)q->limits.max_discard_sectors << 9);
}
static ssize_t queue_discard_max_store(struct request_queue *q,
const char *page, size_t count)
{
unsigned long max_discard;
ssize_t ret = queue_var_store(&max_discard, page, count);
if (ret < 0)
return ret;
if (max_discard & (q->limits.discard_granularity - 1))
return -EINVAL;
max_discard >>= 9;
if (max_discard > UINT_MAX)
return -EINVAL;
if (max_discard > q->limits.max_hw_discard_sectors)
max_discard = q->limits.max_hw_discard_sectors;
q->limits.max_discard_sectors = max_discard;
return ret;
}
static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
{
return queue_var_show(0, page);
}
static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
{
return queue_var_show(0, page);
}
static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
{
return sprintf(page, "%llu\n",
(unsigned long long)q->limits.max_write_zeroes_sectors << 9);
}
static ssize_t queue_zone_write_granularity_show(struct request_queue *q,
char *page)
{
return queue_var_show(queue_zone_write_granularity(q), page);
}
static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
{
unsigned long long max_sectors = q->limits.max_zone_append_sectors;
return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT);
}
static ssize_t
queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
{
unsigned long max_sectors_kb,
max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
page_kb = 1 << (PAGE_SHIFT - 10);
ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
if (ret < 0)
return ret;
max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
q->limits.max_dev_sectors >> 1);
if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
return -EINVAL;
spin_lock_irq(&q->queue_lock);
q->limits.max_sectors = max_sectors_kb << 1;
if (q->disk)
q->disk->bdi->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
spin_unlock_irq(&q->queue_lock);
return ret;
}
static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
{
int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
return queue_var_show(max_hw_sectors_kb, page);
}
static ssize_t queue_virt_boundary_mask_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.virt_boundary_mask, page);
}
#define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
static ssize_t \
queue_##name##_show(struct request_queue *q, char *page) \
{ \
int bit; \
bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags); \
return queue_var_show(neg ? !bit : bit, page); \
} \
static ssize_t \
queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
{ \
unsigned long val; \
ssize_t ret; \
ret = queue_var_store(&val, page, count); \
if (ret < 0) \
return ret; \
if (neg) \
val = !val; \
\
if (val) \
blk_queue_flag_set(QUEUE_FLAG_##flag, q); \
else \
blk_queue_flag_clear(QUEUE_FLAG_##flag, q); \
return ret; \
}
QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
#undef QUEUE_SYSFS_BIT_FNS
static ssize_t queue_zoned_show(struct request_queue *q, char *page)
{
switch (blk_queue_zoned_model(q)) {
case BLK_ZONED_HA:
return sprintf(page, "host-aware\n");
case BLK_ZONED_HM:
return sprintf(page, "host-managed\n");
default:
return sprintf(page, "none\n");
}
}
static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
{
return queue_var_show(blk_queue_nr_zones(q), page);
}
static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_max_open_zones(q), page);
}
static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_max_active_zones(q), page);
}
static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
{
return queue_var_show((blk_queue_nomerges(q) << 1) |
blk_queue_noxmerges(q), page);
}
static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
size_t count)
{
unsigned long nm;
ssize_t ret = queue_var_store(&nm, page, count);
if (ret < 0)
return ret;
blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
if (nm == 2)
blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
else if (nm)
blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
return ret;
}
static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
{
bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
return queue_var_show(set << force, page);
}
static ssize_t
queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
{
ssize_t ret = -EINVAL;
#ifdef CONFIG_SMP
unsigned long val;
ret = queue_var_store(&val, page, count);
if (ret < 0)
return ret;
if (val == 2) {
blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
} else if (val == 1) {
blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
} else if (val == 0) {
blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
}
#endif
return ret;
}
static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
{
int val;
if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
val = BLK_MQ_POLL_CLASSIC;
else
val = q->poll_nsec / 1000;
return sprintf(page, "%d\n", val);
}
static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
size_t count)
{
int err, val;
if (!q->mq_ops || !q->mq_ops->poll)
return -EINVAL;
err = kstrtoint(page, 10, &val);
if (err < 0)
return err;
if (val == BLK_MQ_POLL_CLASSIC)
q->poll_nsec = BLK_MQ_POLL_CLASSIC;
else if (val >= 0)
q->poll_nsec = val * 1000;
else
return -EINVAL;
return count;
}
static ssize_t queue_poll_show(struct request_queue *q, char *page)
{
return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
}
static ssize_t queue_poll_store(struct request_queue *q, const char *page,
size_t count)
{
if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
return -EINVAL;
pr_info_ratelimited("writes to the poll attribute are ignored.\n");
pr_info_ratelimited("please use driver specific parameters instead.\n");
return count;
}
static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
{
return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
}
static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
size_t count)
{
unsigned int val;
int err;
err = kstrtou32(page, 10, &val);
if (err || val == 0)
return -EINVAL;
blk_queue_rq_timeout(q, msecs_to_jiffies(val));
return count;
}
static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
{
if (!wbt_rq_qos(q))
return -EINVAL;
return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
}
static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
size_t count)
{
struct rq_qos *rqos;
ssize_t ret;
s64 val;
ret = queue_var_store64(&val, page);
if (ret < 0)
return ret;
if (val < -1)
return -EINVAL;
rqos = wbt_rq_qos(q);
if (!rqos) {
ret = wbt_init(q);
if (ret)
return ret;
}
if (val == -1)
val = wbt_default_latency_nsec(q);
else if (val >= 0)
val *= 1000ULL;
if (wbt_get_min_lat(q) == val)
return count;
/*
* Ensure that the queue is idled, in case the latency update
* ends up either enabling or disabling wbt completely. We can't
* have IO inflight if that happens.
*/
blk_mq_freeze_queue(q);
blk_mq_quiesce_queue(q);
wbt_set_min_lat(q, val);
blk_mq_unquiesce_queue(q);
blk_mq_unfreeze_queue(q);
return count;
}
static ssize_t queue_wc_show(struct request_queue *q, char *page)
{
if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
return sprintf(page, "write back\n");
return sprintf(page, "write through\n");
}
static ssize_t queue_wc_store(struct request_queue *q, const char *page,
size_t count)
{
int set = -1;
if (!strncmp(page, "write back", 10))
set = 1;
else if (!strncmp(page, "write through", 13) ||
!strncmp(page, "none", 4))
set = 0;
if (set == -1)
return -EINVAL;
if (set)
blk_queue_flag_set(QUEUE_FLAG_WC, q);
else
blk_queue_flag_clear(QUEUE_FLAG_WC, q);
return count;
}
static ssize_t queue_fua_show(struct request_queue *q, char *page)
{
return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
}
static ssize_t queue_dax_show(struct request_queue *q, char *page)
{
return queue_var_show(blk_queue_dax(q), page);
}
#define QUEUE_RO_ENTRY(_prefix, _name) \
static struct queue_sysfs_entry _prefix##_entry = { \
.attr = { .name = _name, .mode = 0444 }, \
.show = _prefix##_show, \
};
#define QUEUE_RW_ENTRY(_prefix, _name) \
static struct queue_sysfs_entry _prefix##_entry = { \
.attr = { .name = _name, .mode = 0644 }, \
.show = _prefix##_show, \
.store = _prefix##_store, \
};
QUEUE_RW_ENTRY(queue_requests, "nr_requests");
QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
QUEUE_RW_ENTRY(elv_iosched, "scheduler");
QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");
QUEUE_RO_ENTRY(queue_chunk_sectors, "chunk_sectors");
QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");
QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
QUEUE_RO_ENTRY(queue_zone_write_granularity, "zone_write_granularity");
QUEUE_RO_ENTRY(queue_zoned, "zoned");
QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
QUEUE_RW_ENTRY(queue_poll, "io_poll");
QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
QUEUE_RW_ENTRY(queue_wc, "write_cache");
QUEUE_RO_ENTRY(queue_fua, "fua");
QUEUE_RO_ENTRY(queue_dax, "dax");
QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
QUEUE_RO_ENTRY(queue_virt_boundary_mask, "virt_boundary_mask");
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
QUEUE_RW_ENTRY(blk_throtl_sample_time, "throttle_sample_time");
#endif
/* legacy alias for logical_block_size: */
static struct queue_sysfs_entry queue_hw_sector_size_entry = {
.attr = {.name = "hw_sector_size", .mode = 0444 },
.show = queue_logical_block_size_show,
};
QUEUE_RW_ENTRY(queue_nonrot, "rotational");
QUEUE_RW_ENTRY(queue_iostats, "iostats");
QUEUE_RW_ENTRY(queue_random, "add_random");
QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
static struct attribute *queue_attrs[] = {
&queue_requests_entry.attr,
&queue_ra_entry.attr,
&queue_max_hw_sectors_entry.attr,
&queue_max_sectors_entry.attr,
&queue_max_segments_entry.attr,
&queue_max_discard_segments_entry.attr,
&queue_max_integrity_segments_entry.attr,
&queue_max_segment_size_entry.attr,
&elv_iosched_entry.attr,
&queue_hw_sector_size_entry.attr,
&queue_logical_block_size_entry.attr,
&queue_physical_block_size_entry.attr,
&queue_chunk_sectors_entry.attr,
&queue_io_min_entry.attr,
&queue_io_opt_entry.attr,
&queue_discard_granularity_entry.attr,
&queue_discard_max_entry.attr,
&queue_discard_max_hw_entry.attr,
&queue_discard_zeroes_data_entry.attr,
&queue_write_same_max_entry.attr,
&queue_write_zeroes_max_entry.attr,
&queue_zone_append_max_entry.attr,
&queue_zone_write_granularity_entry.attr,
&queue_nonrot_entry.attr,
&queue_zoned_entry.attr,
&queue_nr_zones_entry.attr,
&queue_max_open_zones_entry.attr,
&queue_max_active_zones_entry.attr,
&queue_nomerges_entry.attr,
&queue_rq_affinity_entry.attr,
&queue_iostats_entry.attr,
&queue_stable_writes_entry.attr,
&queue_random_entry.attr,
&queue_poll_entry.attr,
&queue_wc_entry.attr,
&queue_fua_entry.attr,
&queue_dax_entry.attr,
&queue_wb_lat_entry.attr,
&queue_poll_delay_entry.attr,
&queue_io_timeout_entry.attr,
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
&blk_throtl_sample_time_entry.attr,
#endif
&queue_virt_boundary_mask_entry.attr,
NULL,
};
static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
int n)
{
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
if (attr == &queue_io_timeout_entry.attr &&
(!q->mq_ops || !q->mq_ops->timeout))
return 0;
if ((attr == &queue_max_open_zones_entry.attr ||
attr == &queue_max_active_zones_entry.attr) &&
!blk_queue_is_zoned(q))
return 0;
return attr->mode;
}
static struct attribute_group queue_attr_group = {
.attrs = queue_attrs,
.is_visible = queue_attr_visible,
};
#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
static ssize_t
queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
{
struct queue_sysfs_entry *entry = to_queue(attr);
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
ssize_t res;
if (!entry->show)
return -EIO;
mutex_lock(&q->sysfs_lock);
res = entry->show(q, page);
mutex_unlock(&q->sysfs_lock);
return res;
}
static ssize_t
queue_attr_store(struct kobject *kobj, struct attribute *attr,
const char *page, size_t length)
{
struct queue_sysfs_entry *entry = to_queue(attr);
struct request_queue *q;
ssize_t res;
if (!entry->store)
return -EIO;
q = container_of(kobj, struct request_queue, kobj);
mutex_lock(&q->sysfs_lock);
res = entry->store(q, page, length);
mutex_unlock(&q->sysfs_lock);
return res;
}
static void blk_free_queue_rcu(struct rcu_head *rcu_head)
{
struct request_queue *q = container_of(rcu_head, struct request_queue,
rcu_head);
kmem_cache_free(blk_get_queue_kmem_cache(blk_queue_has_srcu(q)), q);
}
/**
* blk_release_queue - releases all allocated resources of the request_queue
* @kobj: pointer to a kobject, whose container is a request_queue
*
* This function releases all allocated resources of the request queue.
*
* The struct request_queue refcount is incremented with blk_get_queue() and
* decremented with blk_put_queue(). Once the refcount reaches 0 this function
* is called.
*
* For drivers that have a request_queue on a gendisk and added with
* __device_add_disk() the refcount to request_queue will reach 0 with
* the last put_disk() called by the driver. For drivers which don't use
* __device_add_disk() this happens with blk_cleanup_queue().
*
* Drivers exist which depend on the release of the request_queue to be
* synchronous, it should not be deferred.
*
* Context: can sleep
*/
static void blk_release_queue(struct kobject *kobj)
{
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
might_sleep();
percpu_ref_exit(&q->q_usage_counter);
if (q->poll_stat)
blk_stat_remove_callback(q, q->poll_cb);
blk_stat_free_callback(q->poll_cb);
blk_free_queue_stats(q->stats);
kfree(q->poll_stat);
blk_queue_free_zone_bitmaps(q);
if (queue_is_mq(q))
blk_mq_release(q);
bioset_exit(&q->bio_split);
if (blk_queue_has_srcu(q))
cleanup_srcu_struct(q->srcu);
ida_simple_remove(&blk_queue_ida, q->id);
call_rcu(&q->rcu_head, blk_free_queue_rcu);
}
static const struct sysfs_ops queue_sysfs_ops = {
.show = queue_attr_show,
.store = queue_attr_store,
};
struct kobj_type blk_queue_ktype = {
.sysfs_ops = &queue_sysfs_ops,
.release = blk_release_queue,
};
/**
* blk_register_queue - register a block layer queue with sysfs
* @disk: Disk of which the request queue should be registered with sysfs.
*/
int blk_register_queue(struct gendisk *disk)
{
int ret;
struct device *dev = disk_to_dev(disk);
struct request_queue *q = disk->queue;
ret = blk_trace_init_sysfs(dev);
if (ret)
return ret;
mutex_lock(&q->sysfs_dir_lock);
ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
if (ret < 0) {
blk_trace_remove_sysfs(dev);
goto unlock;
}
ret = sysfs_create_group(&q->kobj, &queue_attr_group);
if (ret) {
blk_trace_remove_sysfs(dev);
kobject_del(&q->kobj);
kobject_put(&dev->kobj);
goto unlock;
}
if (queue_is_mq(q))
__blk_mq_register_dev(dev, q);
mutex_lock(&q->sysfs_lock);
mutex_lock(&q->debugfs_mutex);
q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
blk_debugfs_root);
if (queue_is_mq(q))
blk_mq_debugfs_register(q);
mutex_unlock(&q->debugfs_mutex);
ret = disk_register_independent_access_ranges(disk, NULL);
if (ret)
goto put_dev;
if (q->elevator) {
ret = elv_register_queue(q, false);
if (ret)
goto put_dev;
}
ret = blk_crypto_sysfs_register(q);
if (ret)
goto put_dev;
blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
wbt_enable_default(q);
blk_throtl_register_queue(q);
/* Now everything is ready and send out KOBJ_ADD uevent */
kobject_uevent(&q->kobj, KOBJ_ADD);
if (q->elevator)
kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
mutex_unlock(&q->sysfs_lock);
unlock:
mutex_unlock(&q->sysfs_dir_lock);
/*
* SCSI probing may synchronously create and destroy a lot of
* request_queues for non-existent devices. Shutting down a fully
* functional queue takes measureable wallclock time as RCU grace
* periods are involved. To avoid excessive latency in these
* cases, a request_queue starts out in a degraded mode which is
* faster to shut down and is made fully functional here as
* request_queues for non-existent devices never get registered.
*/
if (!blk_queue_init_done(q)) {
blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
percpu_ref_switch_to_percpu(&q->q_usage_counter);
}
return ret;
put_dev:
elv_unregister_queue(q);
disk_unregister_independent_access_ranges(disk);
mutex_unlock(&q->sysfs_lock);
mutex_unlock(&q->sysfs_dir_lock);
kobject_del(&q->kobj);
blk_trace_remove_sysfs(dev);
kobject_put(&dev->kobj);
return ret;
}
/**
* blk_unregister_queue - counterpart of blk_register_queue()
* @disk: Disk of which the request queue should be unregistered from sysfs.
*
* Note: the caller is responsible for guaranteeing that this function is called
* after blk_register_queue() has finished.
*/
void blk_unregister_queue(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
if (WARN_ON(!q))
return;
/* Return early if disk->queue was never registered. */
if (!blk_queue_registered(q))
return;
/*
* Since sysfs_remove_dir() prevents adding new directory entries
* before removal of existing entries starts, protect against
* concurrent elv_iosched_store() calls.
*/
mutex_lock(&q->sysfs_lock);
blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
mutex_unlock(&q->sysfs_lock);
mutex_lock(&q->sysfs_dir_lock);
/*
* Remove the sysfs attributes before unregistering the queue data
* structures that can be modified through sysfs.
*/
if (queue_is_mq(q))
blk_mq_unregister_dev(disk_to_dev(disk), q);
blk_crypto_sysfs_unregister(q);
blk_trace_remove_sysfs(disk_to_dev(disk));
mutex_lock(&q->sysfs_lock);
elv_unregister_queue(q);
disk_unregister_independent_access_ranges(disk);
mutex_unlock(&q->sysfs_lock);
/* Now that we've deleted all child objects, we can delete the queue. */
kobject_uevent(&q->kobj, KOBJ_REMOVE);
kobject_del(&q->kobj);
mutex_unlock(&q->sysfs_dir_lock);
mutex_lock(&q->debugfs_mutex);
blk_trace_shutdown(q);
debugfs_remove_recursive(q->debugfs_dir);
q->debugfs_dir = NULL;
q->sched_debugfs_dir = NULL;
q->rqos_debugfs_dir = NULL;
mutex_unlock(&q->debugfs_mutex);
kobject_put(&disk_to_dev(disk)->kobj);
}