Messages in this thread Patch in this message | | | From | Can Guo <> | Subject | [PATCH v3 1/1] scsi: pm: Balance pm_only counter of request queue during system resume | Date | Wed, 29 Apr 2020 21:10:05 -0700 |
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During system resume, scsi_resume_device() decreases a request queue's pm_only counter if the scsi device was quiesced before. But after that, if the scsi device's RPM status is RPM_SUSPENDED, the pm_only counter is still held (non-zero). Current scsi resume hook only sets the RPM status of the scsi device and its request queue to RPM_ACTIVE, but leaves the pm_only counter unchanged. This may make the request queue's pm_only counter remain non-zero after resume hook returns, hence those who are waiting on the mq_freeze_wq would never be woken up. Fix this by calling blk_post_runtime_resume() if pm_only is non-zero to balance the pm_only counter which is held by the scsi device's RPM ops.
(struct request_queue)0xFFFFFF815B69E938 pm_only = (counter = 2), rpm_status = 0, dev = 0xFFFFFF815B0511A0,
((struct device)0xFFFFFF815B0511A0)).power is_suspended = FALSE, runtime_status = RPM_ACTIVE,
(struct scsi_device)0xFFFFFF815b051000 request_queue = 0xFFFFFF815B69E938, sdev_state = SDEV_RUNNING, quiesced_by = 0x0,
B::v.f_/task_ -000|__switch_to -001|context_switch -001|__schedule -002|schedule -003|blk_queue_enter(q = 0xFFFFFF815B69E938, flags = 0) -004|generic_make_request -005|submit_bio
Signed-off-by: Can Guo <cang@codeaurora.org> ---
Change since v2: - Rebased on 5.8-scsi-queue
Change since v1: - Added more debugging context info
drivers/scsi/scsi_pm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c index 3717eea..4804029 100644 --- a/drivers/scsi/scsi_pm.c +++ b/drivers/scsi/scsi_pm.c @@ -93,8 +93,10 @@ static int scsi_dev_type_resume(struct device *dev, */ if (!err && scsi_is_sdev_device(dev)) { struct scsi_device *sdev = to_scsi_device(dev); - - blk_set_runtime_active(sdev->request_queue); + if (blk_queue_pm_only(sdev->request_queue)) + blk_post_runtime_resume(sdev->request_queue, 0); + else + blk_set_runtime_active(sdev->request_queue); } } -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
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