scsi: scsi_debug: Get command abort feature working again

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The command abort feature allows us to test aborting a command which has
timed-out.

The idea is that for specific commands we just don't call scsi_done() and
allow the request to timeout, which ensures SCSI EH kicks-in we try to
abort the command.

Since commit 4a0c6f432d ("scsi: scsi_debug: Add new defer type for
mq_poll") this does not seem to work. The issue is that we clear the
sd_dp->aborted flag in schedule_resp() before the completion callback has
run. When the completion callback actually runs, it calls scsi_done() as
normal as sd_dp->aborted unset. This is all very racy.

Fix by not clearing sd_dp->aborted in schedule_resp(). Also move the call
to blk_abort_request() from schedule_resp() to sdebug_q_cmd_complete(),
which makes the code have a more logical sequence.

I also note that this feature only works for commands which are classed as
"SDEG_RES_IMMED_MASK", but only practically triggered with prior RW
commands. So for my experiment I need to run fio to trigger the error on
the "nth" command (see inject_on_this_cmd()), and then run something like
sg_sync to queue a command to actually trigger the abort.

Signed-off-by: John Garry <john.g.garry@oracle.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Link: https://lore.kernel.org/r/20230313093114.1498305-11-john.g.garry@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

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This commit is contained in:

John Garry 2023-03-13 09:31:13 +00:00 • committed by Martin K. Petersen

parent 151f0ec9dd

commit f037b5cb07

1 changed files with 8 additions and 9 deletions

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drivers/scsi/scsi_debug.c

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