From: Vasu Dev Date: Fri, 27 Feb 2009 18:56:27 +0000 (-0800) Subject: [SCSI] fcoe: Out of order tx frames was causing several check condition SCSI status X-Git-Tag: v2.6.29~41^2~8 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c826a3145736e3baabebccfd0aecfbb6dae059f2;p=pandora-kernel.git [SCSI] fcoe: Out of order tx frames was causing several check condition SCSI status frames followed by these errors in log. [sdp] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK [sdp] Sense Key : Aborted Command [current] [sdp] Add. Sense: Data phase error This was causing some test apps to exit due to write failure under heavy load. This was due to a race around adding and removing tx frame skb in fcoe_pending_queue, Chris Leech helped me to find that brief unlocking period when pulling skb from fcoe_pending_queue in various contexts (fcoe_watchdog and fcoe_xmit) and then adding skb back into fcoe_pending_queue up on a failed fcoe_start_io could change skb/tx frame order in fcoe_pending_queue. Thanks Chris. This patch allows only single context to pull skb from fcoe_pending_queue at any time to prevent above described ordering issue/race by use of fcoe_pending_queue_active flag. This patch simplified fcoe_watchdog with modified fcoe_check_wait_queue by use of FCOE_LOW_QUEUE_DEPTH instead previously used several conditionals to clear and set lp->qfull. I think FCOE_MAX_QUEUE_DEPTH with FCOE_LOW_QUEUE_DEPTH will work better in re/setting lp->qfull and these could be fine tuned for performance. Signed-off-by: Vasu Dev Signed-off-by: Robert Love Signed-off-by: James Bottomley --- Reading git-diff-tree failed