From 2fb965cc7b46832a2ea083375a02389e93d013c4 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 11 Jan 2019 12:07:00 +0100 Subject: [PATCH] blk-wbt: move disable check into get_limit() BugLink: https://bugs.launchpad.net/bugs/1810998 Check it in one place, instead of in multiple places. Tested-by: Anchal Agarwal Signed-off-by: Jens Axboe (backported from commit ffa358dcaae1f2f00926484e712e06daa8953cb4) [mfo: backport: - blk-wbt.c: - hunk 1: refresh lower context lines due to lack of commit 782f569774d7 ("blk-wbt: throttle discards like background writes"), not required / introduces a new thing/behavior.] - hunk 2: s/rq_wait_inc_below(rqw/atomic_inc_below(&rqw->inflight/ - hunk 3: s/rq_wait_inc_below(rqw/atomic_inc_below(&rqw->inflight/ Signed-off-by: Mauricio Faria de Oliveira Acked-by: Stefan Bader Acked-by: Kleber Sacilotto de Souza Signed-off-by: Kleber Sacilotto de Souza --- block/blk-wbt.c | 22 +++++++--------------- 1 file changed, 7 insertions(+), 15 deletions(-) diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 145f192a8007..0d3c01cfe30c 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -483,6 +483,13 @@ static inline unsigned int get_limit(struct rq_wb *rwb, unsigned long rw) { unsigned int limit; + /* + * If we got disabled, just return UINT_MAX. This ensures that + * we'll properly inc a new IO, and dec+wakeup at the end. + */ + if (!rwb_enabled(rwb)) + return UINT_MAX; + /* * At this point we know it's a buffered write. If this is * kswapd trying to free memory, or REQ_SYNC is set, then @@ -517,16 +524,6 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct, struct rq_wait *rqw = get_rq_wait(rwb, wb_acct); DECLARE_WAITQUEUE(wait, current); - /* - * inc it here even if disabled, since we'll dec it at completion. - * this only happens if the task was sleeping in __wbt_wait(), - * and someone turned it off at the same time. - */ - if (!rwb_enabled(rwb)) { - atomic_inc(&rqw->inflight); - return; - } - if (!waitqueue_active(&rqw->wait) && atomic_inc_below(&rqw->inflight, get_limit(rwb, rw))) return; @@ -535,11 +532,6 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct, do { set_current_state(TASK_UNINTERRUPTIBLE); - if (!rwb_enabled(rwb)) { - atomic_inc(&rqw->inflight); - break; - } - if (atomic_inc_below(&rqw->inflight, get_limit(rwb, rw))) break; -- 2.39.2