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-rw-r--r--block/blk-sysfs.c977
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);
+}