linux/block/blk-sysfs.c
Jan Kara 8330cdb0fe block: Make writeback throttling defaults consistent for SQ devices
When CFQ is used as an elevator, it disables writeback throttling
because they don't play well together. Later when a different elevator
is chosen for the device, writeback throttling doesn't get enabled
again as it should. Make sure CFQ enables writeback throttling (if it
should be enabled by default) when we switch from it to another IO
scheduler.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-19 08:49:03 -06:00

937 lines
23 KiB
C

/*
* 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/blk-cgroup.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-wbt.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 (!q->request_fn && !q->mq_ops)
return -EINVAL;
ret = queue_var_store(&nr, page, count);
if (ret < 0)
return ret;
if (nr < BLKDEV_MIN_RQ)
nr = BLKDEV_MIN_RQ;
if (q->request_fn)
err = blk_update_nr_requests(q, nr);
else
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 = q->backing_dev_info->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 = queue_var_store(&ra_kb, page, count);
if (ret < 0)
return ret;
q->backing_dev_info->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)
{
if (blk_queue_cluster(q))
return queue_var_show(queue_max_segment_size(q), (page));
return queue_var_show(PAGE_SIZE, (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 sprintf(page, "%llu\n",
(unsigned long long)q->limits.max_write_same_sectors << 9);
}
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_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;
q->backing_dev_info->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));
}
#define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
static ssize_t \
queue_show_##name(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_store_##name(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; \
\
spin_lock_irq(q->queue_lock); \
if (val) \
queue_flag_set(QUEUE_FLAG_##flag, q); \
else \
queue_flag_clear(QUEUE_FLAG_##flag, q); \
spin_unlock_irq(q->queue_lock); \
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);
#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_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;
spin_lock_irq(q->queue_lock);
queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
if (nm == 2)
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
else if (nm)
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
spin_unlock_irq(q->queue_lock);
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;
spin_lock_irq(q->queue_lock);
if (val == 2) {
queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
} else if (val == 1) {
queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
} else if (val == 0) {
queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
}
spin_unlock_irq(q->queue_lock);
#endif
return ret;
}
static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
{
int val;
if (q->poll_nsec == -1)
val = -1;
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 == -1)
q->poll_nsec = -1;
else
q->poll_nsec = val * 1000;
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)
{
unsigned long poll_on;
ssize_t ret;
if (!q->mq_ops || !q->mq_ops->poll)
return -EINVAL;
ret = queue_var_store(&poll_on, page, count);
if (ret < 0)
return ret;
spin_lock_irq(q->queue_lock);
if (poll_on)
queue_flag_set(QUEUE_FLAG_POLL, q);
else
queue_flag_clear(QUEUE_FLAG_POLL, q);
spin_unlock_irq(q->queue_lock);
return ret;
}
static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
{
if (!q->rq_wb)
return -EINVAL;
return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000));
}
static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
size_t count)
{
struct rq_wb *rwb;
ssize_t ret;
s64 val;
ret = queue_var_store64(&val, page);
if (ret < 0)
return ret;
if (val < -1)
return -EINVAL;
rwb = q->rq_wb;
if (!rwb) {
ret = wbt_init(q);
if (ret)
return ret;
rwb = q->rq_wb;
if (!rwb)
return -EINVAL;
}
if (val == -1)
rwb->min_lat_nsec = wbt_default_latency_nsec(q);
else if (val >= 0)
rwb->min_lat_nsec = val * 1000ULL;
if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
rwb->enable_state = WBT_STATE_ON_MANUAL;
wbt_update_limits(rwb);
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;
spin_lock_irq(q->queue_lock);
if (set)
queue_flag_set(QUEUE_FLAG_WC, q);
else
queue_flag_clear(QUEUE_FLAG_WC, q);
spin_unlock_irq(q->queue_lock);
return count;
}
static ssize_t queue_dax_show(struct request_queue *q, char *page)
{
return queue_var_show(blk_queue_dax(q), page);
}
static struct queue_sysfs_entry queue_requests_entry = {
.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
.show = queue_requests_show,
.store = queue_requests_store,
};
static struct queue_sysfs_entry queue_ra_entry = {
.attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
.show = queue_ra_show,
.store = queue_ra_store,
};
static struct queue_sysfs_entry queue_max_sectors_entry = {
.attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
.show = queue_max_sectors_show,
.store = queue_max_sectors_store,
};
static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
.attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
.show = queue_max_hw_sectors_show,
};
static struct queue_sysfs_entry queue_max_segments_entry = {
.attr = {.name = "max_segments", .mode = S_IRUGO },
.show = queue_max_segments_show,
};
static struct queue_sysfs_entry queue_max_discard_segments_entry = {
.attr = {.name = "max_discard_segments", .mode = S_IRUGO },
.show = queue_max_discard_segments_show,
};
static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
.show = queue_max_integrity_segments_show,
};
static struct queue_sysfs_entry queue_max_segment_size_entry = {
.attr = {.name = "max_segment_size", .mode = S_IRUGO },
.show = queue_max_segment_size_show,
};
static struct queue_sysfs_entry queue_iosched_entry = {
.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
.show = elv_iosched_show,
.store = elv_iosched_store,
};
static struct queue_sysfs_entry queue_hw_sector_size_entry = {
.attr = {.name = "hw_sector_size", .mode = S_IRUGO },
.show = queue_logical_block_size_show,
};
static struct queue_sysfs_entry queue_logical_block_size_entry = {
.attr = {.name = "logical_block_size", .mode = S_IRUGO },
.show = queue_logical_block_size_show,
};
static struct queue_sysfs_entry queue_physical_block_size_entry = {
.attr = {.name = "physical_block_size", .mode = S_IRUGO },
.show = queue_physical_block_size_show,
};
static struct queue_sysfs_entry queue_chunk_sectors_entry = {
.attr = {.name = "chunk_sectors", .mode = S_IRUGO },
.show = queue_chunk_sectors_show,
};
static struct queue_sysfs_entry queue_io_min_entry = {
.attr = {.name = "minimum_io_size", .mode = S_IRUGO },
.show = queue_io_min_show,
};
static struct queue_sysfs_entry queue_io_opt_entry = {
.attr = {.name = "optimal_io_size", .mode = S_IRUGO },
.show = queue_io_opt_show,
};
static struct queue_sysfs_entry queue_discard_granularity_entry = {
.attr = {.name = "discard_granularity", .mode = S_IRUGO },
.show = queue_discard_granularity_show,
};
static struct queue_sysfs_entry queue_discard_max_hw_entry = {
.attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
.show = queue_discard_max_hw_show,
};
static struct queue_sysfs_entry queue_discard_max_entry = {
.attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
.show = queue_discard_max_show,
.store = queue_discard_max_store,
};
static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
.attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
.show = queue_discard_zeroes_data_show,
};
static struct queue_sysfs_entry queue_write_same_max_entry = {
.attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
.show = queue_write_same_max_show,
};
static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
.attr = {.name = "write_zeroes_max_bytes", .mode = S_IRUGO },
.show = queue_write_zeroes_max_show,
};
static struct queue_sysfs_entry queue_nonrot_entry = {
.attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
.show = queue_show_nonrot,
.store = queue_store_nonrot,
};
static struct queue_sysfs_entry queue_zoned_entry = {
.attr = {.name = "zoned", .mode = S_IRUGO },
.show = queue_zoned_show,
};
static struct queue_sysfs_entry queue_nomerges_entry = {
.attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
.show = queue_nomerges_show,
.store = queue_nomerges_store,
};
static struct queue_sysfs_entry queue_rq_affinity_entry = {
.attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
.show = queue_rq_affinity_show,
.store = queue_rq_affinity_store,
};
static struct queue_sysfs_entry queue_iostats_entry = {
.attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
.show = queue_show_iostats,
.store = queue_store_iostats,
};
static struct queue_sysfs_entry queue_random_entry = {
.attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
.show = queue_show_random,
.store = queue_store_random,
};
static struct queue_sysfs_entry queue_poll_entry = {
.attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
.show = queue_poll_show,
.store = queue_poll_store,
};
static struct queue_sysfs_entry queue_poll_delay_entry = {
.attr = {.name = "io_poll_delay", .mode = S_IRUGO | S_IWUSR },
.show = queue_poll_delay_show,
.store = queue_poll_delay_store,
};
static struct queue_sysfs_entry queue_wc_entry = {
.attr = {.name = "write_cache", .mode = S_IRUGO | S_IWUSR },
.show = queue_wc_show,
.store = queue_wc_store,
};
static struct queue_sysfs_entry queue_dax_entry = {
.attr = {.name = "dax", .mode = S_IRUGO },
.show = queue_dax_show,
};
static struct queue_sysfs_entry queue_wb_lat_entry = {
.attr = {.name = "wbt_lat_usec", .mode = S_IRUGO | S_IWUSR },
.show = queue_wb_lat_show,
.store = queue_wb_lat_store,
};
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
static struct queue_sysfs_entry throtl_sample_time_entry = {
.attr = {.name = "throttle_sample_time", .mode = S_IRUGO | S_IWUSR },
.show = blk_throtl_sample_time_show,
.store = blk_throtl_sample_time_store,
};
#endif
static struct attribute *default_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,
&queue_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_nonrot_entry.attr,
&queue_zoned_entry.attr,
&queue_nomerges_entry.attr,
&queue_rq_affinity_entry.attr,
&queue_iostats_entry.attr,
&queue_random_entry.attr,
&queue_poll_entry.attr,
&queue_wc_entry.attr,
&queue_dax_entry.attr,
&queue_wb_lat_entry.attr,
&queue_poll_delay_entry.attr,
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
&throtl_sample_time_entry.attr,
#endif
NULL,
};
#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);
if (blk_queue_dying(q)) {
mutex_unlock(&q->sysfs_lock);
return -ENOENT;
}
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);
if (blk_queue_dying(q)) {
mutex_unlock(&q->sysfs_lock);
return -ENOENT;
}
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_requestq_cachep, q);
}
/**
* blk_release_queue: - release a &struct request_queue when it is no longer needed
* @kobj: the kobj belonging to the request queue to be released
*
* Description:
* blk_release_queue is the pair to blk_init_queue() or
* blk_queue_make_request(). It should be called when a request queue is
* being released; typically when a block device is being de-registered.
* Currently, its primary task it to free all the &struct request
* structures that were allocated to the queue and the queue itself.
*
* Note:
* The low level driver must have finished any outstanding requests first
* via blk_cleanup_queue().
**/
static void blk_release_queue(struct kobject *kobj)
{
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
blk_stat_remove_callback(q, q->poll_cb);
blk_stat_free_callback(q->poll_cb);
bdi_put(q->backing_dev_info);
blkcg_exit_queue(q);
if (q->elevator) {
ioc_clear_queue(q);
elevator_exit(q, q->elevator);
}
blk_free_queue_stats(q->stats);
blk_exit_rl(&q->root_rl);
if (q->queue_tags)
__blk_queue_free_tags(q);
if (!q->mq_ops) {
if (q->exit_rq_fn)
q->exit_rq_fn(q, q->fq->flush_rq);
blk_free_flush_queue(q->fq);
} else {
blk_mq_release(q);
}
blk_trace_shutdown(q);
if (q->mq_ops)
blk_mq_debugfs_unregister(q);
if (q->bio_split)
bioset_free(q->bio_split);
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,
.default_attrs = default_attrs,
.release = blk_release_queue,
};
int blk_register_queue(struct gendisk *disk)
{
int ret;
struct device *dev = disk_to_dev(disk);
struct request_queue *q = disk->queue;
if (WARN_ON(!q))
return -ENXIO;
WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags),
"%s is registering an already registered queue\n",
kobject_name(&dev->kobj));
queue_flag_set_unlocked(QUEUE_FLAG_REGISTERED, q);
/*
* 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)) {
queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
percpu_ref_switch_to_percpu(&q->q_usage_counter);
blk_queue_bypass_end(q);
}
ret = blk_trace_init_sysfs(dev);
if (ret)
return ret;
if (q->mq_ops)
blk_mq_register_dev(dev, q);
/* Prevent changes through sysfs until registration is completed. */
mutex_lock(&q->sysfs_lock);
ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
if (ret < 0) {
blk_trace_remove_sysfs(dev);
goto unlock;
}
kobject_uevent(&q->kobj, KOBJ_ADD);
wbt_enable_default(q);
blk_throtl_register_queue(q);
if (q->request_fn || (q->mq_ops && q->elevator)) {
ret = elv_register_queue(q);
if (ret) {
kobject_uevent(&q->kobj, KOBJ_REMOVE);
kobject_del(&q->kobj);
blk_trace_remove_sysfs(dev);
kobject_put(&dev->kobj);
goto unlock;
}
}
ret = 0;
unlock:
mutex_unlock(&q->sysfs_lock);
return ret;
}
void blk_unregister_queue(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
if (WARN_ON(!q))
return;
queue_flag_clear_unlocked(QUEUE_FLAG_REGISTERED, q);
wbt_exit(q);
if (q->mq_ops)
blk_mq_unregister_dev(disk_to_dev(disk), q);
if (q->request_fn || (q->mq_ops && q->elevator))
elv_unregister_queue(q);
kobject_uevent(&q->kobj, KOBJ_REMOVE);
kobject_del(&q->kobj);
blk_trace_remove_sysfs(disk_to_dev(disk));
kobject_put(&disk_to_dev(disk)->kobj);
}