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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
blk-wbt: factor out a helper wbt_set_lat()
To move implementation details inside blk-wbt.c, prepare to fix possible
deadlock to call wbt_init() while queue is frozen in the next patch.
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
authored by
Yu Kuai
and committed by
Jens Axboe
2751b900
06564bae
+51
-45
+2
-37
block/blk-sysfs.c
+2
-37
block/blk-sysfs.c
···
636
636
static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page,
637
637
size_t count)
638
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{
639
-
struct request_queue *q = disk->queue;
640
-
struct rq_qos *rqos;
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ssize_t ret;
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s64 val;
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-
unsigned int memflags;
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ret = queue_var_store64(&val, page);
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if (ret < 0)
···
645
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if (val < -1)
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return -EINVAL;
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-
/*
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-
* Ensure that the queue is idled, in case the latency update
650
-
* ends up either enabling or disabling wbt completely. We can't
651
-
* have IO inflight if that happens.
652
-
*/
653
-
memflags = blk_mq_freeze_queue(q);
654
-
655
-
rqos = wbt_rq_qos(q);
656
-
if (!rqos) {
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-
ret = wbt_init(disk);
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-
if (ret)
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-
goto out;
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-
}
661
-
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-
ret = count;
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-
if (val == -1)
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-
val = wbt_default_latency_nsec(q);
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-
else if (val >= 0)
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-
val *= 1000ULL;
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-
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if (wbt_get_min_lat(q) == val)
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-
goto out;
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-
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-
blk_mq_quiesce_queue(q);
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-
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mutex_lock(&disk->rqos_state_mutex);
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-
wbt_set_min_lat(q, val);
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-
mutex_unlock(&disk->rqos_state_mutex);
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-
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-
blk_mq_unquiesce_queue(q);
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-
out:
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blk_mq_unfreeze_queue(q, memflags);
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-
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-
return ret;
651
+
ret = wbt_set_lat(disk, val);
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+
return ret ? ret : count;
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653
}
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654
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655
QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
+47
-3
block/blk-wbt.c
+47
-3
block/blk-wbt.c
···
93
93
struct rq_depth rq_depth;
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};
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+
static int wbt_init(struct gendisk *disk);
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+
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static inline struct rq_wb *RQWB(struct rq_qos *rqos)
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{
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return container_of(rqos, struct rq_wb, rqos);
···
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return RQWB(rqos)->min_lat_nsec;
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}
510
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-
void wbt_set_min_lat(struct request_queue *q, u64 val)
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+
static void wbt_set_min_lat(struct request_queue *q, u64 val)
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{
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struct rq_qos *rqos = wbt_rq_qos(q);
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if (!rqos)
···
743
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WARN_ON_ONCE(wbt_init(disk));
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742
}
745
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-
u64 wbt_default_latency_nsec(struct request_queue *q)
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+
static u64 wbt_default_latency_nsec(struct request_queue *q)
747
745
{
748
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/*
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* We default to 2msec for non-rotational storage, and 75msec
···
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#endif
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};
905
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-
int wbt_init(struct gendisk *disk)
904
+
static int wbt_init(struct gendisk *disk)
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{
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struct request_queue *q = disk->queue;
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struct rq_wb *rwb;
···
949
947
kfree(rwb);
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return ret;
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949
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+
}
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+
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+
int wbt_set_lat(struct gendisk *disk, s64 val)
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+
{
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+
struct request_queue *q = disk->queue;
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+
unsigned int memflags;
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+
struct rq_qos *rqos;
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+
int ret = 0;
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+
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+
/*
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+
* Ensure that the queue is idled, in case the latency update
961
+
* ends up either enabling or disabling wbt completely. We can't
962
+
* have IO inflight if that happens.
963
+
*/
964
+
memflags = blk_mq_freeze_queue(q);
965
+
966
+
rqos = wbt_rq_qos(q);
967
+
if (!rqos) {
968
+
ret = wbt_init(disk);
969
+
if (ret)
970
+
goto out;
971
+
}
972
+
973
+
if (val == -1)
974
+
val = wbt_default_latency_nsec(q);
975
+
else if (val >= 0)
976
+
val *= 1000ULL;
977
+
978
+
if (wbt_get_min_lat(q) == val)
979
+
goto out;
980
+
981
+
blk_mq_quiesce_queue(q);
982
+
983
+
mutex_lock(&disk->rqos_state_mutex);
984
+
wbt_set_min_lat(q, val);
985
+
mutex_unlock(&disk->rqos_state_mutex);
986
+
987
+
blk_mq_unquiesce_queue(q);
988
+
out:
989
+
blk_mq_unfreeze_queue(q, memflags);
990
+
991
+
return ret;
952
992
}
+2
-5
block/blk-wbt.h
+2
-5
block/blk-wbt.h
···
4
4
5
5
#ifdef CONFIG_BLK_WBT
6
6
7
-
int wbt_init(struct gendisk *disk);
8
7
void wbt_init_enable_default(struct gendisk *disk);
9
8
void wbt_disable_default(struct gendisk *disk);
10
9
void wbt_enable_default(struct gendisk *disk);
11
10
12
11
u64 wbt_get_min_lat(struct request_queue *q);
13
-
void wbt_set_min_lat(struct request_queue *q, u64 val);
14
-
bool wbt_disabled(struct request_queue *);
15
-
16
-
u64 wbt_default_latency_nsec(struct request_queue *);
12
+
bool wbt_disabled(struct request_queue *q);
13
+
int wbt_set_lat(struct gendisk *disk, s64 val);
17
14
18
15
#else
19
16