diff options
Diffstat (limited to 'block/blk-iolatency.c')
| -rw-r--r-- | block/blk-iolatency.c | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c index 2560708b9109..fd5fec989e39 100644 --- a/block/blk-iolatency.c +++ b/block/blk-iolatency.c @@ -755,7 +755,7 @@ static void blkiolatency_enable_work_fn(struct work_struct *work) } } -int blk_iolatency_init(struct gendisk *disk) +static int blk_iolatency_init(struct gendisk *disk) { struct blk_iolatency *blkiolat; int ret; @@ -824,6 +824,29 @@ 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); + if (ret) + return ret; + + /* + * 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; +} + static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { @@ -838,6 +861,10 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf, blkg_conf_init(&ctx, buf); + ret = blk_iolatency_try_init(&ctx); + if (ret) + goto out; + ret = blkg_conf_prep(blkcg, &blkcg_policy_iolatency, &ctx); if (ret) goto out; |