From: Alan Stern <stern@rowland.harvard.edu>
To: Martin Kepplinger <martin.kepplinger@puri.sm>
Cc: Bart Van Assche <bvanassche@acm.org>,
Can Guo <cang@codeaurora.org>,
linux-scsi@vger.kernel.org, linux-block@vger.kernel.org,
kernel@puri.sm
Subject: Re: [PATCH] block: Fix bug in runtime-resume handling
Date: Mon, 24 Aug 2020 16:13:43 -0400 [thread overview]
Message-ID: <20200824201343.GA344424@rowland.harvard.edu> (raw)
In-Reply-To: <3e5a465e-8fe0-b379-a80e-23e2f588c71a@acm.org>
On Mon, Aug 24, 2020 at 10:48:32AM -0700, Bart Van Assche wrote:
> On 2020-08-23 07:57, Alan Stern wrote:
> > The problem is fixed by checking that the queue's runtime-PM status
> > isn't RPM_SUSPENDED before allowing a request to be issued, [ ... ]
>
> Reviewed-by: Bart Van Assche <bvanassche@acm.org>
>
> Can, can you help with testing this patch?
>
> Thanks,
>
> Bart.
Martin:
(I forgot to ask this question several weeks ago, while you were running
your tests. Better ask it now before I forget again...)
I suspect the old runtime-PM code in the block layer would have worked
okay in your SD cardreader test if the BLK_MQ_REQ_PREEMPT flag had not
been set. Do you know why the flag was set, or what line of code caused
it to be set?
As I recall, the request that failed was a read-ahead. It's not clear
to me why such a request would need to have BLK_MQ_REQ_PREEMPT set.
Although there may be other reasons for having that flag, at this point
we're concerned with requests that are part of the runtime-resume
procedure. A read-ahead does not fall into that category.
Do you think you can find the answer? Perhaps we should add a separate
BLK_MQ_REQ_PM flag.
Alan Stern
next prev parent reply other threads:[~2020-08-24 20:13 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 11:10 [PATCH] scsi: sd: add runtime pm to open / release Martin Kepplinger
2020-06-24 13:33 ` Bart Van Assche
2020-06-25 8:16 ` Martin Kepplinger
2020-06-25 14:52 ` Alan Stern
2020-06-26 3:53 ` Bart Van Assche
2020-06-26 15:07 ` Bart Van Assche
2020-06-26 15:44 ` Alan Stern
2020-06-28 2:37 ` Bart Van Assche
2020-06-28 13:10 ` Alan Stern
2020-06-29 9:42 ` Martin Kepplinger
2020-06-29 16:15 ` Alan Stern
2020-06-29 16:56 ` Bart Van Assche
2020-06-29 17:40 ` Alan Stern
2020-06-30 3:33 ` Martin Kepplinger
2020-06-30 13:38 ` Alan Stern
2020-06-30 15:59 ` Bart Van Assche
2020-06-30 18:02 ` Alan Stern
2020-06-30 19:23 ` Bart Van Assche
2020-06-30 19:38 ` Alan Stern
2020-06-30 23:31 ` Bart Van Assche
2020-07-01 0:49 ` Alan Stern
2020-07-06 16:41 ` Alan Stern
2020-07-28 7:02 ` Martin Kepplinger
2020-07-28 20:02 ` Alan Stern
2020-07-29 14:12 ` Martin Kepplinger
2020-07-29 14:32 ` Alan Stern
2020-07-29 14:44 ` Martin K. Petersen
2020-07-29 14:56 ` Alan Stern
2020-07-29 14:46 ` James Bottomley
2020-07-29 14:53 ` James Bottomley
2020-07-29 15:40 ` Martin Kepplinger
2020-07-29 15:44 ` James Bottomley
2020-07-29 16:43 ` Martin Kepplinger
2020-07-29 18:25 ` Alan Stern
2020-07-29 18:29 ` James Bottomley
2020-07-30 8:52 ` Martin Kepplinger
2020-07-30 8:54 ` Martin Kepplinger
2020-07-30 15:10 ` Alan Stern
2020-08-04 9:39 ` Martin Kepplinger
2020-08-07 9:51 ` Martin Kepplinger
2020-08-07 14:30 ` Alan Stern
2020-08-08 6:59 ` Martin Kepplinger
2020-08-08 15:05 ` Alan Stern
2020-08-09 9:20 ` Martin Kepplinger
2020-08-09 15:26 ` Alan Stern
2020-08-10 12:03 ` Martin Kepplinger
2020-08-10 14:13 ` Alan Stern
2020-08-11 7:55 ` Martin Kepplinger
2020-08-11 13:48 ` Alan Stern
2020-08-23 14:57 ` [PATCH] block: Fix bug in runtime-resume handling Alan Stern
2020-08-24 17:48 ` Bart Van Assche
2020-08-24 20:13 ` Alan Stern [this message]
2020-08-26 7:48 ` Martin Kepplinger
2020-08-27 17:42 ` Martin Kepplinger
2020-08-27 20:29 ` Alan Stern
2020-08-29 7:24 ` Martin Kepplinger
2020-08-29 15:26 ` Alan Stern
2020-08-29 16:33 ` Martin Kepplinger
2020-08-29 18:56 ` Alan Stern
2020-08-30 0:38 ` Bart Van Assche
2020-08-30 1:06 ` Alan Stern
2020-07-29 15:40 ` [PATCH] scsi: sd: add runtime pm to open / release Alan Stern
2020-07-29 15:49 ` James Bottomley
2020-07-29 16:17 ` Alan Stern
2020-07-29 15:52 ` Martin Kepplinger
2020-07-29 18:10 ` Douglas Gilbert
2020-07-30 8:05 ` Martin Kepplinger
2020-07-30 15:14 ` Alan Stern
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