lkml.org 
[lkml]   [2021]   [Jul]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.13 251/800] block, bfq: fix delayed stable merge check
    Date
    From: Luca Mariotti <mariottiluca1@hotmail.it>

    [ Upstream commit e03f2ab78a4a673e4af23c3b855591c48b9de4d7 ]

    When attempting to schedule a merge of a given bfq_queue with the currently
    in-service bfq_queue or with a cooperating bfq_queue among the scheduled
    bfq_queues, delayed stable merge is checked for rotational or non-queueing
    devs. For this stable merge to be performed, some conditions must be met.
    If the current bfq_queue underwent some split from some merged bfq_queue,
    one of these conditions is that two hundred milliseconds must elapse from
    split, otherwise this condition is always met.

    Unfortunately, by mistake, time_is_after_jiffies() was written instead of
    time_is_before_jiffies() for this check, verifying that less than two
    hundred milliseconds have elapsed instead of verifying that at least two
    hundred milliseconds have elapsed.

    Fix this issue by replacing time_is_after_jiffies() with
    time_is_before_jiffies().

    Signed-off-by: Luca Mariotti <mariottiluca1@hotmail.it>
    Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
    Signed-off-by: Pietro Pedroni <pedroni.pietro.96@gmail.com>
    Link: https://lore.kernel.org/r/20210619140948.98712-3-paolo.valente@linaro.org
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    block/bfq-iosched.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
    index acd1f881273e..2adb1e69c9d2 100644
    --- a/block/bfq-iosched.c
    +++ b/block/bfq-iosched.c
    @@ -2697,7 +2697,7 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
    if (unlikely(!bfqd->nonrot_with_queueing)) {
    if (bic->stable_merge_bfqq &&
    !bfq_bfqq_just_created(bfqq) &&
    - time_is_after_jiffies(bfqq->split_time +
    + time_is_before_jiffies(bfqq->split_time +
    msecs_to_jiffies(200))) {
    struct bfq_queue *stable_merge_bfqq =
    bic->stable_merge_bfqq;
    --
    2.30.2


    \
     
     \ /
      Last update: 2021-07-12 10:29    [W:3.397 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site