In preparation to further simplify and group sysfs attributes which
don't require locking or require some form of locking other than q->
limits_lock, move acquire/release of q->sysfs_lock and queue freeze/
unfreeze under each attributes' respective show/store method.
While we are at it, also remove ->load_module() as it's used to load
the module before queue is freezed. Now as we moved queue-freeze under
->store(), we could load module directly from the attributes' store
method before we actually start freezing the queue. Currently, the
->load_module() is only used by "scheduler" attribute, so we now load
the relevant elevator module before we start freezing the queue in
elv_iosched_store().
Signed-off-by: Nilay Shroff <nilay@xxxxxxxxxxxxx>
---
block/blk-sysfs.c | 210 +++++++++++++++++++++++++++++++---------------
block/elevator.c | 20 ++++-
2 files changed, 162 insertions(+), 68 deletions(-)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index d3af3079c2bd..fcfbe59f3a56 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -28,8 +28,6 @@ struct queue_sysfs_entry {
ssize_t (*store)(struct gendisk *disk, const char *page, size_t count);
int (*store_limit)(struct gendisk *disk, const char *page,
size_t count, struct queue_limits *lim);
-
- void (*load_module)(struct gendisk *disk, const char *page, size_t count);
};
static ssize_t
@@ -55,7 +53,12 @@ queue_var_store(unsigned long *var, const char *page, size_t count)
static ssize_t queue_requests_show(struct gendisk *disk, char *page)
{
- return queue_var_show(disk->queue->nr_requests, page);
+ ssize_t ret;
+
+ mutex_lock(&disk->queue->sysfs_lock);
+ ret = queue_var_show(disk->queue->nr_requests, page);
+ mutex_unlock(&disk->queue->sysfs_lock);
+ return ret;
}
static ssize_t
@@ -63,27 +66,38 @@ queue_requests_store(struct gendisk *disk, const char *page, size_t count)
{
unsigned long nr;
int ret, err;
+ unsigned int memflags;
+ struct request_queue *q = disk->queue;
- if (!queue_is_mq(disk->queue))
+ if (!queue_is_mq(q))
return -EINVAL;
ret = queue_var_store(&nr, page, count);
if (ret < 0)
return ret;
+ mutex_lock(&q->sysfs_lock);
+ memflags = blk_mq_freeze_queue(q);
if (nr < BLKDEV_MIN_RQ)
nr = BLKDEV_MIN_RQ;
err = blk_mq_update_nr_requests(disk->queue, nr);
if (err)
- return err;
-
+ ret = err;
+ blk_mq_unfreeze_queue(q, memflags);
+ mutex_unlock(&q->sysfs_lock);
return ret;
}
static ssize_t queue_ra_show(struct gendisk *disk, char *page)
{
- return queue_var_show(disk->bdi->ra_pages << (PAGE_SHIFT - 10), page);
+ ssize_t ret;
+
+ mutex_lock(&disk->queue->sysfs_lock);
+ ret = queue_var_show(disk->bdi->ra_pages << (PAGE_SHIFT - 10), page);
+ mutex_unlock(&disk->queue->sysfs_lock);
+
+ return ret;
}
static ssize_t
@@ -91,11 +105,19 @@ queue_ra_store(struct gendisk *disk, const char *page, size_t count)
{
unsigned long ra_kb;
ssize_t ret;
+ unsigned int memflags;
+ struct request_queue *q = disk->queue;
ret = queue_var_store(&ra_kb, page, count);
if (ret < 0)
return ret;
+
+ mutex_lock(&q->sysfs_lock);
+ memflags = blk_mq_freeze_queue(q);
disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
+ blk_mq_unfreeze_queue(q, memflags);
+ mutex_unlock(&q->sysfs_lock);
+
return ret;
}
@@ -150,7 +172,12 @@ QUEUE_SYSFS_LIMIT_SHOW_SECTORS_TO_KB(max_hw_sectors)
#define QUEUE_SYSFS_SHOW_CONST(_name, _val) \
static ssize_t queue_##_name##_show(struct gendisk *disk, char *page) \
{ \
- return sysfs_emit(page, "%d\n", _val); \
+ ssize_t ret; \
+ \
+ mutex_lock(&disk->queue->sysfs_lock); \
+ ret = sysfs_emit(page, "%d\n", _val); \
+ mutex_unlock(&disk->queue->sysfs_lock); \
+ return ret; \
}
/* deprecated fields */
@@ -239,10 +266,17 @@ QUEUE_SYSFS_FEATURE_SHOW(dax, BLK_FEAT_DAX);
static ssize_t queue_poll_show(struct gendisk *disk, char *page)
{
- if (queue_is_mq(disk->queue))
- return sysfs_emit(page, "%u\n", blk_mq_can_poll(disk->queue));
- return sysfs_emit(page, "%u\n",
- !!(disk->queue->limits.features & BLK_FEAT_POLL));
+ ssize_t ret;
+
+ mutex_lock(&disk->queue->sysfs_lock);
+ if (queue_is_mq(disk->queue)) {
+ ret = sysfs_emit(page, "%u\n", blk_mq_can_poll(disk->queue));
+ } else {
+ ret = sysfs_emit(page, "%u\n",
+ !!(disk->queue->limits.features & BLK_FEAT_POLL));
+ }
+ mutex_unlock(&disk->queue->sysfs_lock);
+ return ret;
}
static ssize_t queue_zoned_show(struct gendisk *disk, char *page)
@@ -254,7 +288,12 @@ static ssize_t queue_zoned_show(struct gendisk *disk, char *page)
static ssize_t queue_nr_zones_show(struct gendisk *disk, char *page)
{
- return queue_var_show(disk_nr_zones(disk), page);
+ ssize_t ret;
+
+ mutex_lock(&disk->queue->sysfs_lock);
+ ret = queue_var_show(disk_nr_zones(disk), page);
+ mutex_unlock(&disk->queue->sysfs_lock);
+ return ret;
}
static ssize_t queue_iostats_passthrough_show(struct gendisk *disk, char *page)
@@ -281,35 +320,51 @@ static int queue_iostats_passthrough_store(struct gendisk *disk,
static ssize_t queue_nomerges_show(struct gendisk *disk, char *page)
{
- return queue_var_show((blk_queue_nomerges(disk->queue) << 1) |
+ ssize_t ret;
+
+ mutex_lock(&disk->queue->sysfs_lock);
+ ret = queue_var_show((blk_queue_nomerges(disk->queue) << 1) |
blk_queue_noxmerges(disk->queue), page);
+ mutex_unlock(&disk->queue->sysfs_lock);
+ return ret;
}
static ssize_t queue_nomerges_store(struct gendisk *disk, const char *page,
size_t count)
{
unsigned long nm;
+ unsigned int memflags;
+ struct request_queue *q = disk->queue;
ssize_t ret = queue_var_store(&nm, page, count);
if (ret < 0)
return ret;
- blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, disk->queue);
- blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, disk->queue);
+ mutex_lock(&q->sysfs_lock);
+ memflags = blk_mq_freeze_queue(q);
+ 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, disk->queue);
+ blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
else if (nm)
- blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, disk->queue);
+ blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
+ blk_mq_unfreeze_queue(q, memflags);
+ mutex_unlock(&q->sysfs_lock);
return ret;
}
static ssize_t queue_rq_affinity_show(struct gendisk *disk, char *page)
{
- bool set = test_bit(QUEUE_FLAG_SAME_COMP, &disk->queue->queue_flags);
- bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &disk->queue->queue_flags);
+ ssize_t ret;
+ bool set, force;
- return queue_var_show(set << force, page);
+ mutex_lock(&disk->queue->sysfs_lock);
+ set = test_bit(QUEUE_FLAG_SAME_COMP, &disk->queue->queue_flags);
+ force = test_bit(QUEUE_FLAG_SAME_FORCE, &disk->queue->queue_flags);
+ ret = queue_var_show(set << force, page);
+ mutex_unlock(&disk->queue->sysfs_lock);
+ return ret;
}
static ssize_t
@@ -319,11 +374,14 @@ queue_rq_affinity_store(struct gendisk *disk, const char *page, size_t count)
#ifdef CONFIG_SMP
struct request_queue *q = disk->queue;
unsigned long val;
+ unsigned int memflags;
ret = queue_var_store(&val, page, count);
if (ret < 0)
return ret;
+ mutex_lock(&q->sysfs_lock);
+ memflags = blk_mq_freeze_queue(q);
if (val == 2) {
blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
@@ -334,6 +392,8 @@ queue_rq_affinity_store(struct gendisk *disk, const char *page, size_t count)
blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
}
+ blk_mq_unfreeze_queue(q, memflags);
+ mutex_unlock(&q->sysfs_lock);
#endif
return ret;
}
@@ -347,29 +407,52 @@ static ssize_t queue_poll_delay_store(struct gendisk *disk, const char *page,
static ssize_t queue_poll_store(struct gendisk *disk, const char *page,
size_t count)
{
- if (!(disk->queue->limits.features & BLK_FEAT_POLL))
- return -EINVAL;
+ unsigned int memflags;
+ ssize_t ret = count;
+ struct request_queue *q = disk->queue;
+
+ mutex_lock(&q->sysfs_lock);
+ memflags = blk_mq_freeze_queue(q);
+ if (!(q->limits.features & BLK_FEAT_POLL)) {
+ ret = -EINVAL;
+ goto out;
+ }
pr_info_ratelimited("writes to the poll attribute are ignored.\n");
pr_info_ratelimited("please use driver specific parameters instead.\n");
- return count;
+out:
+ blk_mq_unfreeze_queue(q, memflags);
+ mutex_unlock(&q->sysfs_lock);
+
+ return ret;
}
static ssize_t queue_io_timeout_show(struct gendisk *disk, char *page)
{
- return sysfs_emit(page, "%u\n", jiffies_to_msecs(disk->queue->rq_timeout));
+ ssize_t ret;
+
+ mutex_lock(&disk->queue->sysfs_lock);
+ ret = sysfs_emit(page, "%u\n",
+ jiffies_to_msecs(disk->queue->rq_timeout));
+ mutex_unlock(&disk->queue->sysfs_lock);
+ return ret;
}
static ssize_t queue_io_timeout_store(struct gendisk *disk, const char *page,
size_t count)
{
- unsigned int val;
+ unsigned int val, memflags;
int err;
+ struct request_queue *q = disk->queue;
err = kstrtou32(page, 10, &val);
if (err || val == 0)
return -EINVAL;
- blk_queue_rq_timeout(disk->queue, msecs_to_jiffies(val));
+ mutex_lock(&q->sysfs_lock);
+ memflags = blk_mq_freeze_queue(q);
+ blk_queue_rq_timeout(q, msecs_to_jiffies(val));
+ blk_mq_unfreeze_queue(q, memflags);
+ mutex_unlock(&q->sysfs_lock);
return count;
}
@@ -428,14 +511,6 @@ static struct queue_sysfs_entry _prefix##_entry = { \
.store_limit = _prefix##_store, \
}
-#define QUEUE_RW_LOAD_MODULE_ENTRY(_prefix, _name) \
-static struct queue_sysfs_entry _prefix##_entry = { \
- .attr = { .name = _name, .mode = 0644 }, \
- .show = _prefix##_show, \
- .load_module = _prefix##_load_module, \
- .store = _prefix##_store, \
-}
-
QUEUE_RW_ENTRY(queue_requests, "nr_requests");
QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
QUEUE_LIM_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
@@ -443,7 +518,7 @@ QUEUE_LIM_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
QUEUE_LIM_RO_ENTRY(queue_max_segments, "max_segments");
QUEUE_LIM_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
QUEUE_LIM_RO_ENTRY(queue_max_segment_size, "max_segment_size");
-QUEUE_RW_LOAD_MODULE_ENTRY(elv_iosched, "scheduler");
+QUEUE_RW_ENTRY(elv_iosched, "scheduler");
QUEUE_LIM_RO_ENTRY(queue_logical_block_size, "logical_block_size");
QUEUE_LIM_RO_ENTRY(queue_physical_block_size, "physical_block_size");
@@ -512,14 +587,24 @@ static ssize_t queue_var_store64(s64 *var, const char *page)
static ssize_t queue_wb_lat_show(struct gendisk *disk, char *page)
{
- if (!wbt_rq_qos(disk->queue))
- return -EINVAL;
+ ssize_t ret;
+ struct request_queue *q = disk->queue;
- if (wbt_disabled(disk->queue))
- return sysfs_emit(page, "0\n");
+ mutex_lock(&q->sysfs_lock);
+ if (!wbt_rq_qos(q)) {
+ ret = -EINVAL;
+ goto out;
+ }
- return sysfs_emit(page, "%llu\n",
- div_u64(wbt_get_min_lat(disk->queue), 1000));
+ if (wbt_disabled(q)) {
+ ret = sysfs_emit(page, "0\n");
+ goto out;
+ }
+
+ ret = sysfs_emit(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
+out:
+ mutex_unlock(&q->sysfs_lock);
+ return ret;
}
static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page,
@@ -529,6 +614,7 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page,
struct rq_qos *rqos;
ssize_t ret;
s64 val;
+ unsigned int memflags;
ret = queue_var_store64(&val, page);
if (ret < 0)
@@ -536,20 +622,24 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page,
if (val < -1)
return -EINVAL;
+ mutex_lock(&q->sysfs_lock);
+ memflags = blk_mq_freeze_queue(q);
+
rqos = wbt_rq_qos(q);
if (!rqos) {
ret = wbt_init(disk);
if (ret)
- return ret;
+ goto out;
}
+ ret = count;
if (val == -1)
val = wbt_default_latency_nsec(q);
else if (val >= 0)
val *= 1000ULL;
if (wbt_get_min_lat(q) == val)
- return count;
+ goto out;
/*
* Ensure that the queue is idled, in case the latency update
@@ -561,8 +651,11 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page,
wbt_set_min_lat(q, val);
blk_mq_unquiesce_queue(q);
+out:
+ blk_mq_unfreeze_queue(q, memflags);
+ mutex_unlock(&q->sysfs_lock);
- return count;
+ return ret;
}
QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
@@ -684,22 +777,20 @@ queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
{
struct queue_sysfs_entry *entry = to_queue(attr);
struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
- ssize_t res;
if (!entry->show && !entry->show_limit)
return -EIO;
if (entry->show_limit) {
+ ssize_t res;
+
mutex_lock(&disk->queue->limits_lock);
res = entry->show_limit(disk, page);
mutex_unlock(&disk->queue->limits_lock);
return res;
}
- mutex_lock(&disk->queue->sysfs_lock);
- res = entry->show(disk, page);
- mutex_unlock(&disk->queue->sysfs_lock);
- return res;
+ return entry->show(disk, page);
}
static ssize_t
@@ -709,21 +800,13 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
struct queue_sysfs_entry *entry = to_queue(attr);
struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
struct request_queue *q = disk->queue;
- unsigned int memflags;
- ssize_t res;
if (!entry->store_limit && !entry->store)
return -EIO;
- /*
- * If the attribute needs to load a module, do it before freezing the
- * queue to ensure that the module file can be read when the request
- * queue is the one for the device storing the module file.
- */
- if (entry->load_module)
- entry->load_module(disk, page, length);
-
if (entry->store_limit) {
+ ssize_t res;
+
struct queue_limits lim = queue_limits_start_update(q);
res = entry->store_limit(disk, page, length, &lim);
@@ -738,12 +821,7 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
return length;
}
- mutex_lock(&q->sysfs_lock);
- memflags = blk_mq_freeze_queue(q);
- res = entry->store(disk, page, length);
- blk_mq_unfreeze_queue(q, memflags);
- mutex_unlock(&q->sysfs_lock);
- return res;
+ return entry->store(disk, page, length);
}
static const struct sysfs_ops queue_sysfs_ops = {
diff --git a/block/elevator.c b/block/elevator.c
index cd2ce4921601..041f1d983bc7 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -723,11 +723,24 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf,
{
char elevator_name[ELV_NAME_MAX];
int ret;
+ unsigned int memflags;
+ struct request_queue *q = disk->queue;
+ /*
+ * If the attribute needs to load a module, do it before freezing the
+ * queue to ensure that the module file can be read when the request
+ * queue is the one for the device storing the module file.
+ */
+ elv_iosched_load_module(disk, buf, count);
strscpy(elevator_name, buf, sizeof(elevator_name));
- ret = elevator_change(disk->queue, strstrip(elevator_name));
+
+ mutex_lock(&q->sysfs_lock);
+ memflags = blk_mq_freeze_queue(q);
+ ret = elevator_change(q, strstrip(elevator_name));
if (!ret)
- return count;
+ ret = count;
+ blk_mq_unfreeze_queue(q, memflags);
+ mutex_unlock(&q->sysfs_lock);
return ret;
}
@@ -738,6 +751,7 @@ ssize_t elv_iosched_show(struct gendisk *disk, char *name)
struct elevator_type *cur = NULL, *e;
int len = 0;
+ mutex_lock(&q->sysfs_lock);
if (!q->elevator) {
len += sprintf(name+len, "[none] ");
} else {
@@ -755,6 +769,8 @@ ssize_t elv_iosched_show(struct gendisk *disk, char *name)
spin_unlock(&elv_list_lock);
len += sprintf(name+len, "\n");
+ mutex_unlock(&q->sysfs_lock);
+
return len;
}
--
2.47.1
