[3.8.y.z extended stable] Patch "[SCSI] sd: Reduce buffer size for vpd request" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    [SCSI] sd: Reduce buffer size for vpd request

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.14.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 625c3ecc65900c54e21f54aa3e3d816bad924467 Mon Sep 17 00:00:00 2001
From: Bernd Schubert <bernd.schubert at itwm.fraunhofer.de>
Date: Mon, 23 Sep 2013 14:47:32 +0200
Subject: [SCSI] sd: Reduce buffer size for vpd request

commit af73623f5f10eb3832c87a169b28f7df040a875b upstream.

Somehow older areca firmware versions have issues with
scsi_get_vpd_page() and a large buffer, the firmware
seems to crash and the scsi error-handler will start endless
recovery retries.
Limiting the buf-size to 64-bytes fixes this issue with older
firmware versions (<1.49 for my controller).

Fixes a regression with areca controllers and older firmware versions
introduced by commit: 66c28f97120e8a621afd5aa7a31c4b85c547d33d

Reported-by: Nix <nix at esperi.org.uk>
Tested-by: Nix <nix at esperi.org.uk>
Signed-off-by: Bernd Schubert <bernd.schubert at itwm.fraunhofer.de>
Acked-by: Martin K. Petersen <martin.petersen at oracle.com>
Signed-off-by: James Bottomley <JBottomley at Parallels.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/scsi/sd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index bc108d2..a4dc067 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2640,13 +2640,16 @@ static void sd_read_write_same(struct scsi_disk *sdkp, unsigned char *buffer)
 	struct scsi_device *sdev = sdkp->device;

 	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, INQUIRY) < 0) {
+		/* too large values might cause issues with arcmsr */
+		int vpd_buf_len = 64;
+
 		sdev->no_report_opcodes = 1;

 		/* Disable WRITE SAME if REPORT SUPPORTED OPERATION
 		 * CODES is unsupported and the device has an ATA
 		 * Information VPD page (SAT).
 		 */
-		if (!scsi_get_vpd_page(sdev, 0x89, buffer, SD_BUF_SIZE))
+		if (!scsi_get_vpd_page(sdev, 0x89, buffer, vpd_buf_len))
 			sdev->no_write_same = 1;
 	}

--
1.8.3.2