evie/android_kernel_oneplus_msm8998
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block: don't allow nr_pending to go negative

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nr_pending can go negative if we attempt to decrement it without matching
increment call earlier. If nr_pending goes negative, LLD's runtime suspend
might race with the ongoing request. This change allows decrementing
nr_pending only if it is non-zero.

Change-Id: I5f1e93ab0e0f950307e2e3c4f95c7cb01e83ffdd
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
This commit is contained in:
Subhash Jadavani 2015-12-10 17:38:22 -08:00 • committed by David Keitel
parent a627c73479
commit 09ed2d9d3c
2 changed files with 5 additions and 3 deletions
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6
block/blk-core.c
View file

@ -1446,8 +1446,10 @@ EXPORT_SYMBOL_GPL(part_round_stats);
#ifdef CONFIG_PM
static void blk_pm_put_request(struct request *rq)
{
if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending)
pm_runtime_mark_last_busy(rq->q->dev);
if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && rq->q->nr_pending) {
if (!--rq->q->nr_pending)
pm_runtime_mark_last_busy(rq->q->dev);
}
}
#else
static inline void blk_pm_put_request(struct request *rq) {}

2
block/elevator.c
View file

@ -538,7 +538,7 @@ void elv_bio_merged(struct request_queue *q, struct request *rq,
#ifdef CONFIG_PM
static void blk_pm_requeue_request(struct request *rq)
{
if (rq->q->dev && !(rq->cmd_flags & REQ_PM))
if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && rq->q->nr_pending)
rq->q->nr_pending--;
}