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[SCSI] libiscsi: fix cmd timeout/completion race 

If the driver/lib has called scsi_done and cleaned up internally but
scsi layer has not yet called blk_mark_rq_complete when the command
times out we hit a problem if the timeout code calls blk_mark_rq_complete first.
When the time out code calls into the driver we were returning
BLK_EH_RESET_TIMER and that causes the timeout code to just call
us again later.

We need to be calling BLK_EH_HANDLED so the timeout code can complete
the completion process because it had called blk_mark_rq_complete
on the command and now owns its processing.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Mike Christie 2012-01-26 21:13:11 -06:00 committed by James Bottomley
parent 1304be5fe0
commit e3d338a536
1 changed files with 10 additions and 10 deletions
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20
drivers/scsi/libiscsi.c
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@ -1909,6 +1909,16 @@ static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
ISCSI_DBG_EH(session, "scsi cmd %p timedout\n", sc);
spin_lock(&session->lock);
task = (struct iscsi_task *)sc->SCp.ptr;
if (!task) {
/*
* Raced with completion. Blk layer has taken ownership
* so let timeout code complete it now.
*/
rc = BLK_EH_HANDLED;
goto done;
}
if (session->state != ISCSI_STATE_LOGGED_IN) {
/*
* We are probably in the middle of iscsi recovery so let
@ -1925,16 +1935,6 @@ static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
goto done;
}
task = (struct iscsi_task *)sc->SCp.ptr;
if (!task) {
/*
* Raced with completion. Just reset timer, and let it
* complete normally
*/
rc = BLK_EH_RESET_TIMER;
goto done;
}
/*
* If we have sent (at least queued to the network layer) a pdu or
* recvd one for the task since the last timeout ask for