在 2023/08/04 19:36, Li Lingfeng 写道:
From: Li Lingfeng <lilingfeng3@xxxxxxxxxx>
Commit a13696b83da4 ("blk-iolatency: Make initialization lazy") adds
a mutex named "init_mutex" in blk_iolatency_try_init for the race
condition of initializing RQ_QOS_LATENCY.
Now a new lock has been add to struct request_queue by commit a13bd91be223
("block/rq_qos: protect rq_qos apis with a new lock"). And it has been
held in blkg_conf_open_bdev before calling blk_iolatency_init.
So it's not necessary to keep init_mutex in blk_iolatency_try_init, just
remove it.
LGTM
Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Signed-off-by: Li Lingfeng <lilingfeng3@xxxxxxxxxx>
---
block/blk-iolatency.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index fd5fec989e39..8fbd6bc96acb 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -826,7 +826,6 @@ static void iolatency_clear_scaling(struct blkcg_gq *blkg)
static int blk_iolatency_try_init(struct blkg_conf_ctx *ctx)
{
- static DEFINE_MUTEX(init_mutex);
int ret;
ret = blkg_conf_open_bdev(ctx);
@@ -837,13 +836,9 @@ static int blk_iolatency_try_init(struct blkg_conf_ctx *ctx)
* blk_iolatency_init() may fail after rq_qos_add() succeeds which can
* confuse iolat_rq_qos() test. Make the test and init atomic.
*/
- mutex_lock(&init_mutex);
-
if (!iolat_rq_qos(ctx->bdev->bd_queue))
ret = blk_iolatency_init(ctx->bdev->bd_disk);
- mutex_unlock(&init_mutex);
-
return ret;
}
