[PATCH] scsi: increase scsi device's iodone_cnt in scsi_timeout()

[PATCH] scsi: increase scsi device's iodone_cnt in scsi_timeout()

[Wenchao Hao]

The iodone_cnt might be less than iorequest_cnt because
we did not increase the iodone_cnt when a command is done
from timeout.

Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
---
 drivers/scsi/scsi_error.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 448748e3fba5..d21ae0090166 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -355,6 +355,7 @@ enum blk_eh_timer_return scsi_timeout(struct request *req)
 		 */
 		if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
 			return BLK_EH_RESET_TIMER;
+		atomic_inc(&scmd->device->iodone_cnt);
 		if (scsi_abort_command(scmd) != SUCCESS) {
 			set_host_byte(scmd, DID_TIME_OUT);
 			scsi_eh_scmd_add(scmd);
-- 
2.35.3

Re: [PATCH] scsi: increase scsi device's iodone_cnt in scsi_timeout()

[Steffen Maier]

On 8/15/22 18:43, Wenchao Hao wrote:
> The iodone_cnt might be less than iorequest_cnt because
> we did not increase the iodone_cnt when a command is done
> from timeout.
> 
> Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
> ---
>   drivers/scsi/scsi_error.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> index 448748e3fba5..d21ae0090166 100644
> --- a/drivers/scsi/scsi_error.c
> +++ b/drivers/scsi/scsi_error.c
> @@ -355,6 +355,7 @@ enum blk_eh_timer_return scsi_timeout(struct request *req)
>   		 */
>   		if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
>   			return BLK_EH_RESET_TIMER;
> +		atomic_inc(&scmd->device->iodone_cnt);
>   		if (scsi_abort_command(scmd) != SUCCESS) {
>   			set_host_byte(scmd, DID_TIME_OUT);
>   			scsi_eh_scmd_add(scmd);

Not sure, but can't we still get a (late) regular completion even after the 
timeout happened (double accounting) and before we successfully aborted the 
command?


-- 
Mit freundlichen Gruessen / Kind regards
Steffen Maier

Linux on IBM Z and LinuxONE

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Re: [PATCH] scsi: increase scsi device's iodone_cnt in scsi_timeout()

[wenchao hao]

On Tue, Aug 16, 2022 at 12:53 AM Steffen Maier <maier@linux.ibm.com> wrote:
>
> On 8/15/22 18:43, Wenchao Hao wrote:
> > The iodone_cnt might be less than iorequest_cnt because
> > we did not increase the iodone_cnt when a command is done
> > from timeout.
> >
> > Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
> > ---
> >   drivers/scsi/scsi_error.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> > index 448748e3fba5..d21ae0090166 100644
> > --- a/drivers/scsi/scsi_error.c
> > +++ b/drivers/scsi/scsi_error.c
> > @@ -355,6 +355,7 @@ enum blk_eh_timer_return scsi_timeout(struct request *req)
> >                */
> >               if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
> >                       return BLK_EH_RESET_TIMER;
> > +             atomic_inc(&scmd->device->iodone_cnt);
> >               if (scsi_abort_command(scmd) != SUCCESS) {
> >                       set_host_byte(scmd, DID_TIME_OUT);
> >                       scsi_eh_scmd_add(scmd);
>
> Not sure, but can't we still get a (late) regular completion even after the
> timeout happened (double accounting) and before we successfully aborted the
> command?
>
>
The flag SCMD_STATE_COMPLETE would take care of it, this would make
sure a scsi command
is done from timeout or regular completion exclusively.

When scsi_abort_command() begins to handle a command, the command
would be finished by
scsi_finish_command() or retried by requeue function.

If a command finished by scsi_finish_command(), it would not add the iodone_cnt.
If a command is requeued, it would call scsi_dispatch_cmd() again and
another iorequest_cnt would be
added.

According to above analysis, I think it's suitable to increase iodone_cnt here.

Re: [PATCH] scsi: increase scsi device's iodone_cnt in scsi_timeout()

[Wu Bo]

On 2022/8/16 0:43, Wenchao Hao wrote:
> The iodone_cnt might be less than iorequest_cnt because
> we did not increase the iodone_cnt when a command is done
> from timeout.
> 
> Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
> ---
>   drivers/scsi/scsi_error.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> index 448748e3fba5..d21ae0090166 100644
> --- a/drivers/scsi/scsi_error.c
> +++ b/drivers/scsi/scsi_error.c
> @@ -355,6 +355,7 @@ enum blk_eh_timer_return scsi_timeout(struct request *req)
>   		 */
>   		if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
>   			return BLK_EH_RESET_TIMER;
> +		atomic_inc(&scmd->device->iodone_cnt);
>   		if (scsi_abort_command(scmd) != SUCCESS) {
>   			set_host_byte(scmd, DID_TIME_OUT);
>   			scsi_eh_scmd_add(scmd);

Reviewed-by: Wu Bo <wubo40@huawei.com>
-- 
Wu Bo