From: Martin Kepplinger <martin.kepplinger@puri.sm>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Bart Van Assche <bvanassche@acm.org>,
jejb@linux.ibm.com, Can Guo <cang@codeaurora.org>,
martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel@puri.sm
Subject: Re: [PATCH] scsi: sd: add runtime pm to open / release
Date: Tue, 30 Jun 2020 05:33:25 +0200 [thread overview]
Message-ID: <823057f0-95cf-bfcf-c39f-ca5d7abe2372@puri.sm> (raw)
In-Reply-To: <20200629161536.GA405175@rowland.harvard.edu>
On 29.06.20 18:15, Alan Stern wrote:
> On Mon, Jun 29, 2020 at 11:42:59AM +0200, Martin Kepplinger wrote:
>>
>>
>> On 26.06.20 17:44, Alan Stern wrote:
>>> Martin's best approach would be to add some debugging code to find out why
>>> blk_queue_enter() isn't calling bkl_pm_request_resume(), or why that call
>>> doesn't lead to pm_request_resume().
>>>
>>> Alan Stern
>>>
>>
>> Hi Alan,
>>
>> blk_queue_enter() always - especially when sd is runtime suspended and I
>> try to mount as above - sets success to be true for me, so never
>> continues down to bkl_pm_request_resume(). All I see is "PM: Removing
>> info for No Bus:sda1".
>
> Aha. Looking at this more closely, it's apparent that the code in
> blk-core.c contains a logic bug: It assumes that if the BLK_MQ_REQ_PREEMPT
> flag is set then the request can be issued regardless of the queue's
> runtime status. That is not correct when the queue is suspended.
>
> Below is my attempt to fix this up. I'm not sure that the patch is
> entirely correct, but it should fix this logic bug. I would appreciate a
> critical review.
>
> Martin, does this fix the problem?
>
not quite: mounting works and resuming itself indeed happens now when
copying a file, but the I/O itself doesn't, but says "device offline or
changed":
[ 167.167615] sd 0:0:0:0: [sda] tag#0 UNKNOWN(0x2003) Result:
hostbyte=0x00 driverbyte=0x08 cmd_age=0s
[ 167.167630] sd 0:0:0:0: [sda] tag#0 Sense Key : 0x6 [current]
[ 167.167638] sd 0:0:0:0: [sda] tag#0 ASC=0x28 ASCQ=0x0
[ 167.167648] sd 0:0:0:0: [sda] tag#0 CDB: opcode=0x28 28 00 00 00 24
c2 00 00 01 00
[ 167.167658] blk_update_request: I/O error, dev sda, sector 9410 op
0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ 167.178327] FAT-fs (sda1): FAT read failed (blocknr 1218)
[ 167.183895] sd 0:0:0:0: [sda] tag#0 device offline or changed
[ 167.189695] blk_update_request: I/O error, dev sda, sector 5101888 op
0x0:(READ) flags 0x80700 phys_seg 8 prio class 0
[ 167.200510] sd 0:0:0:0: [sda] tag#0 device offline or changed
and a later try to copy a file only yields (mostly my own debug prints):
[ 371.110798] blk_queue_enter: wait_event: pm=0
[ 371.300666] scsi_runtime_resume
[ 371.303834] scsi_runtime_resume
[ 371.307007] scsi_runtime_resume
[ 371.310213] sd 0:0:0:0: [sda] tag#0 device offline or changed
[ 371.316011] blk_update_request: I/O error, dev sda, sector 5101888 op
0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ 372.560690] scsi_runtime_suspend
[ 372.563968] scsi_runtime_suspend
[ 372.567237] scsi_runtime_suspend
thanks Alan for taking the time and trying to fix this! you're close.
what is missing?
martin
next prev parent reply other threads:[~2020-06-30 3:34 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 [this message]
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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=823057f0-95cf-bfcf-c39f-ca5d7abe2372@puri.sm \
--to=martin.kepplinger@puri.sm \
--cc=bvanassche@acm.org \
--cc=cang@codeaurora.org \
--cc=jejb@linux.ibm.com \
--cc=kernel@puri.sm \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=stern@rowland.harvard.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).