| Message ID | 1586841875-15667-1-git-send-email-cang@codeaurora.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/1] scsi: pm: Balance pm_only counter of request queue during system resume | expand |
Loop more... On 2020-04-14 13:24, Can Guo wrote: > 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_0xFFFFFF810C246940 > -000|__switch_to(prev = 0xFFFFFF810C246940, next = 0xFFFFFF80A49357C0) > -001|context_switch(inline) > -001|__schedule(?) > -002|schedule() > -003|blk_queue_enter(q = 0xFFFFFF815B69E938, flags = 0) > -004|generic_make_request(?) > -005|submit_bio(bio = 0xFFFFFF80A8195B80) > > Signed-off-by: Can Guo <cang@codeaurora.org> > > 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); > } > }
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); } }
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_0xFFFFFF810C246940 -000|__switch_to(prev = 0xFFFFFF810C246940, next = 0xFFFFFF80A49357C0) -001|context_switch(inline) -001|__schedule(?) -002|schedule() -003|blk_queue_enter(q = 0xFFFFFF815B69E938, flags = 0) -004|generic_make_request(?) -005|submit_bio(bio = 0xFFFFFF80A8195B80) Signed-off-by: Can Guo <cang@codeaurora.org> Change since v1: - Added more debugging context info --- drivers/scsi/scsi_pm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)