Re: [PATCH v1 6/6] scsi: ufs: Update the fast abort path in ufshcd_abort() for PM requests

On 2021-05-14 12:05, Bart Van Assche wrote:

On 5/12/21 10:55 PM, Can Guo wrote:

quoted

If PM requests fail during runtime suspend/resume, RPM framework saves 
the
error to dev->power.runtime_error. Before the runtime_error gets 
cleared,
runtime PM on this specific device won't work again, leaving the 
device
in either suspended or active state permanently.

When task abort happens to a PM request sent during runtime 
suspend/resume,
even if it can be successfully aborted, RPM framework anyways saves 
the
(TIMEOUT) error. But we want more and we can do better - let error 
handling
recover and clear the runtime_error. So, let PM requests take the fast
abort path in ufshcd_abort().

The only RQF_PM requests I know of are START STOP UNIT and SYNCHRONIZE
CACHE. Are there devices for which these commands can time out or do
these commands perhaps only time out as the result of error injection?

There are also REQUEST SENSE requests sent with RQF_PM flag set from
pm ops. And they do time out (device does not respond in 60s) in real
cases, at least I have seen quite a lot of related issues reported
from customers these years.

quoted

-	if (lrbp->lun == UFS_UPIU_UFS_DEVICE_WLUN) {
+	if (lrbp->lun == UFS_UPIU_UFS_DEVICE_WLUN ||
+	    (cmd->request->rq_flags & RQF_PM)) {

Which are the RQF_PM commands that are not sent to a WLUN? Are these
START STOP UNIT and SYNCHRONIZE CACHE only?

There are also REQUEST SENSE cmds sent to the RPMB W-LU, in 
ufshcd_add_wlus(),
ufshcd_err_handler() and ufshcd_rpmb_resume() and/or ufshcd_wl_resume().

And SYNCHRONIZE CACHE cmd is only sent to general LUs, but not W-LUs.

Thanks,
Can Guo.

Thanks,

Bart.