Commit 21837896 authored Sep 17, 2013 by Eddie Wai Committed by James Bottomley Oct 25, 2013

[SCSI] bnx2fc: Fixed a SCSI CMD cmpl race condition between ABTS and CLEANUP



In the case when a SCSI_CMD times out, bnx2fc will initiate the sending of the
ABTS.  However, if the SCSI layer's SCSI command timer also times out, it'll
instantiate a task abort of the same xid.

The race condition this patch tries to fix is as follows:

SCSI_CMD timeout (20s)
thread 1                   thread 2
send ABTS
rx ABTS cmpl
                           task abort_eh
                           explicit LOGO since ABTS was engaged
                           CLEANUP cmpl
SCSI_CMD cmpl (ABTS cmpl)
instantiate RRQ
wait 10s
attempt to send RRQ (because of LOGO, it wouldn't continue)

Note that there is no call to scsi_done for this SCSI_CMD cmpletion
in this path.

The patch changes the path of execution to call scsi_done immediately
instead of instantiating the RRQ.

Signed-off-by: Eddie Wai <eddie.wai@broadcom.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

parent 97c2730c

drivers/scsi/bnx2fc/bnx2fc_io.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1246,6 +1246,12 @@ int bnx2fc_eh_abort(struct scsi_cmnd *sc_cmd)
		kref_put(&io_req->refcount,
		bnx2fc_cmd_release); /* drop timer hold */
		rc = bnx2fc_expl_logo(lport, io_req);
		/* This only occurs when an task abort was requested while ABTS
		is in progress. Setting the IO_CLEANUP flag will skip the
		RRQ process in the case when the fw generated SCSI_CMD cmpl
		was a result from the ABTS request rather than the CLEANUP
		request */
		set_bit(BNX2FC_FLAG_IO_CLEANUP, &io_req->req_flags);
		goto out;
		}