diff options
Diffstat (limited to 'block/blk-sysfs.c')
| -rw-r--r-- | block/blk-sysfs.c | 977 |
1 files changed, 977 insertions, 0 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c new file mode 100644 index 000000000..9174137a9 --- /dev/null +++ b/block/blk-sysfs.c @@ -0,0 +1,977 @@ +// 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/blk-cgroup.h> +#include <linux/debugfs.h> + +#include "blk.h" +#include "blk-mq.h" +#include "blk-mq-debugfs.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 (!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 = 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) +{ + 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 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_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; + 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_##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) +{ + unsigned long poll_on; + ssize_t ret; + + if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL || + !q->tag_set->map[HCTX_TYPE_POLL].nr_queues) + return -EINVAL; + + ret = queue_var_store(&poll_on, page, count); + if (ret < 0) + return ret; + + if (poll_on) + blk_queue_flag_set(QUEUE_FLAG_POLL, q); + else + blk_queue_flag_clear(QUEUE_FLAG_POLL, q); + + return ret; +} + +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_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"); + +#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_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 + 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); + + percpu_ref_exit(&q->q_usage_counter); + kmem_cache_free(blk_requestq_cachep, q); +} + +/* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */ +static void blk_exit_queue(struct request_queue *q) +{ + /* + * Since the I/O scheduler exit code may access cgroup information, + * perform I/O scheduler exit before disassociating from the block + * cgroup controller. + */ + if (q->elevator) { + ioc_clear_queue(q); + __elevator_exit(q, q->elevator); + } + + /* + * Remove all references to @q from the block cgroup controller before + * restoring @q->queue_lock to avoid that restoring this pointer causes + * e.g. blkcg_print_blkgs() to crash. + */ + blkcg_exit_queue(q); + + /* + * Since the cgroup code may dereference the @q->backing_dev_info + * pointer, only decrease its reference count after having removed the + * association with the block cgroup controller. + */ + bdi_put(q->backing_dev_info); +} + +/** + * 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(); + + 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); + + blk_free_queue_stats(q->stats); + + if (queue_is_mq(q)) { + struct blk_mq_hw_ctx *hctx; + int i; + + cancel_delayed_work_sync(&q->requeue_work); + + queue_for_each_hw_ctx(q, hctx, i) + cancel_delayed_work_sync(&hctx->run_work); + } + + blk_exit_queue(q); + + blk_queue_free_zone_bitmaps(q); + + if (queue_is_mq(q)) + blk_mq_release(q); + + blk_trace_shutdown(q); + mutex_lock(&q->debugfs_mutex); + debugfs_remove_recursive(q->debugfs_dir); + mutex_unlock(&q->debugfs_mutex); + + if (queue_is_mq(q)) + blk_mq_debugfs_unregister(q); + + bioset_exit(&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, + .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; + + if (WARN_ON(!q)) + return -ENXIO; + + WARN_ONCE(blk_queue_registered(q), + "%s is registering an already registered queue\n", + kobject_name(&dev->kobj)); + + /* + * 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); + } + + blk_queue_update_readahead(q); + + 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; + } + + mutex_lock(&q->debugfs_mutex); + q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent), + blk_debugfs_root); + mutex_unlock(&q->debugfs_mutex); + + if (queue_is_mq(q)) { + __blk_mq_register_dev(dev, q); + blk_mq_debugfs_register(q); + } + + mutex_lock(&q->sysfs_lock); + if (q->elevator) { + ret = elv_register_queue(q, false); + if (ret) { + 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_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); + + ret = 0; +unlock: + mutex_unlock(&q->sysfs_dir_lock); + return ret; +} +EXPORT_SYMBOL_GPL(blk_register_queue); + +/** + * 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_trace_remove_sysfs(disk_to_dev(disk)); + + mutex_lock(&q->sysfs_lock); + if (q->elevator) + elv_unregister_queue(q); + 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); + + kobject_put(&disk_to_dev(disk)->kobj); +} |