[4.2.y-ckt stable] Patch "scsi: add Synology to 1024 sector blacklist" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

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

    scsi: add Synology to 1024 sector blacklist

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt3.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 90ec7d32bbcf0493b6cdeda48f3a1fbc3af69c69 Mon Sep 17 00:00:00 2001
From: Mike Christie <mchristi at redhat.com>
Date: Thu, 7 Jan 2016 16:34:05 -0600
Subject: scsi: add Synology to 1024 sector blacklist

commit 9055082fb100cc66e20c048251d05159f5f2cfba upstream.

Another iscsi target that cannot handle large IOs, but does not tell us
a limit.

The Synology iSCSI targets report:

Block limits VPD page (SBC):
  Write same no zero (WSNZ): 0
  Maximum compare and write length: 0 blocks
  Optimal transfer length granularity: 0 blocks
  Maximum transfer length: 0 blocks
  Optimal transfer length: 0 blocks
  Maximum prefetch length: 0 blocks
  Maximum unmap LBA count: 0
  Maximum unmap block descriptor count: 0
  Optimal unmap granularity: 0
  Unmap granularity alignment valid: 0
  Unmap granularity alignment: 0
  Maximum write same length: 0x0 blocks

and the size of the command it can handle seems to depend on how much
memory it can allocate at the time. This results in IO errors when
handling large IOs. This patch just has us use the old 1024 default
sectors for this target by adding it to the scsi blacklist. We do not
have good contacs with this vendors, so I have not been able to try and
fix on their side.

I have posted this a long while back, but it was not merged. This
version just fixes it up for merge/patch failures in the original
version.

Reported-by: Ancoron Luciferis <ancoron.luciferis at googlemail.com>
Reported-by: Michael Meyers <steltek at tcnnet.com>
Signed-off-by: Mike Christie <mchristi at redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/scsi/scsi_devinfo.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
index 9f77d23..64ed88a 100644
--- a/drivers/scsi/scsi_devinfo.c
+++ b/drivers/scsi/scsi_devinfo.c
@@ -227,6 +227,7 @@ static struct {
 	{"Promise", "VTrak E610f", NULL, BLIST_SPARSELUN | BLIST_NO_RSOC},
 	{"Promise", "", NULL, BLIST_SPARSELUN},
 	{"QNAP", "iSCSI Storage", NULL, BLIST_MAX_1024},
+	{"SYNOLOGY", "iSCSI Storage", NULL, BLIST_MAX_1024},
 	{"QUANTUM", "XP34301", "1071", BLIST_NOTQ},
 	{"REGAL", "CDC-4X", NULL, BLIST_MAX5LUN | BLIST_SINGLELUN},
 	{"SanDisk", "ImageMate CF-SD1", NULL, BLIST_FORCELUN},
--
1.9.1