Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932294Ab1EHTA3 (ORCPT ); Sun, 8 May 2011 15:00:29 -0400 Received: from artax.karlin.mff.cuni.cz ([195.113.26.195]:53847 "EHLO artax.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932253Ab1EHTA1 (ORCPT ); Sun, 8 May 2011 15:00:27 -0400 Date: Sun, 8 May 2011 21:00:26 +0200 (CEST) From: Mikulas Patocka To: Matthew Wilcox , "James E.J. Bottomley" cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] sym53c8xx_2: avoid data corruption when disk rejects commands with QUEUE FULL Message-ID: User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) X-Personality-Disorder: Schizoid MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2260 Lines: 52 [ the maintainer is not responding, so I'm sending this to other people ] sym53c8xx_2: avoid data corruption when disk rejects commands with QUEUE FULL When the controller encounters an error (including QUEUE FULL or BUSY status), it aborts all not yet submitted requests in the function sym_dequeue_from_squeue. This function aborts them with DID_SOFT_ERROR. If the disk has a full tag queue, the request that caused the overflow is aborted with QUEUE FULL status (and the scsi midlayer properly retries it until it is accepted by the disk), but other requests are aborted with DID_SOFT_ERROR --- for them, the midlayer does just a few retries and then signals the error up to sd. The result is that disk returning QUEUE FULL causes request failures. The error was reproduced on 53c895 with COMPAQ BD03685A24 disk (rebranded ST336607LC) with command queue 48 or 64 tags. The disk has 64 tags, but under some access patterns it return QUEUE FULL when there are less than 64 pending tags. The SCSI specification allows returning QUEUE FULL anytime and it is up to the host to retry. Signed-off-by: Mikulas Patocka --- drivers/scsi/sym53c8xx_2/sym_hipd.c | 4 ++++ 1 file changed, 4 insertions(+) Index: linux-2.6.36-rc5-fast/drivers/scsi/sym53c8xx_2/sym_hipd.c =================================================================== --- linux-2.6.36-rc5-fast.orig/drivers/scsi/sym53c8xx_2/sym_hipd.c 2010-09-27 10:25:59.000000000 +0200 +++ linux-2.6.36-rc5-fast/drivers/scsi/sym53c8xx_2/sym_hipd.c 2010-09-27 10:26:27.000000000 +0200 @@ -3000,7 +3000,11 @@ sym_dequeue_from_squeue(struct sym_hcb * if ((target == -1 || cp->target == target) && (lun == -1 || cp->lun == lun) && (task == -1 || cp->tag == task)) { +#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING sym_set_cam_status(cp->cmd, DID_SOFT_ERROR); +#else + sym_set_cam_status(cp->cmd, DID_REQUEUE); +#endif sym_remque(&cp->link_ccbq); sym_insque_tail(&cp->link_ccbq, &np->comp_ccbq); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/