[SCSI] libiscsi: fix cmd timeout/completion race (e3d338a5) · Commits · 戴 / test

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>

drivers/scsi/libiscsi.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -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

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