releases/4.18.14/blk-mq-i-o-and-timer-unplugs-are-inverted-in-blktrace.patch

   1 From 587562d0c7cd6861f4f90a2eb811cccb1a376f5f Mon Sep 17 00:00:00 2001
   2 From: Ilya Dryomov <idryomov@gmail.com>
   3 Date: Wed, 26 Sep 2018 14:35:50 +0200
   4 Subject: blk-mq: I/O and timer unplugs are inverted in blktrace
   5
   6 From: Ilya Dryomov <idryomov@gmail.com>
   7
   8 commit 587562d0c7cd6861f4f90a2eb811cccb1a376f5f upstream.
   9
  10 trace_block_unplug() takes true for explicit unplugs and false for
  11 implicit unplugs.  schedule() unplugs are implicit and should be
  12 reported as timer unplugs.  While correct in the legacy code, this has
  13 been inverted in blk-mq since 4.11.
  14
  15 Cc: stable@vger.kernel.org
  16 Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers")
  17 Reviewed-by: Omar Sandoval <osandov@fb.com>
  18 Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
  19 Signed-off-by: Jens Axboe <axboe@kernel.dk>
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  21
  22 ---
  23  block/blk-mq.c |    4 ++--
  24  1 file changed, 2 insertions(+), 2 deletions(-)
  25
  26 --- a/block/blk-mq.c
  27 +++ b/block/blk-mq.c
  28 @@ -1596,7 +1596,7 @@ void blk_mq_flush_plug_list(struct blk_p
  29                 BUG_ON(!rq->q);
  30                 if (rq->mq_ctx != this_ctx) {
  31                         if (this_ctx) {
  32 -                               trace_block_unplug(this_q, depth, from_schedule);
  33 +                               trace_block_unplug(this_q, depth, !from_schedule);
  34                                 blk_mq_sched_insert_requests(this_q, this_ctx,
  35                                                                 &ctx_list,
  36                                                                 from_schedule);
  37 @@ -1616,7 +1616,7 @@ void blk_mq_flush_plug_list(struct blk_p
  38          * on 'ctx_list'. Do those.
  39          */
  40         if (this_ctx) {
  41 -               trace_block_unplug(this_q, depth, from_schedule);
  42 +               trace_block_unplug(this_q, depth, !from_schedule);
  43                 blk_mq_sched_insert_requests(this_q, this_ctx, &ctx_list,
  44                                                 from_schedule);
  45         }