[3.19.y-ckt stable] Patch "libata: add ATA_HORKAGE_MAX_SEC_1024 to revert back to previous max_sectors limit" has been added to staging queue

[Kamal Mostafa]

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

    libata: add ATA_HORKAGE_MAX_SEC_1024 to revert back to previous max_sectors limit

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt6.

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

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 4ea7890d73285f3ce96257376ee5a91b86649090 Mon Sep 17 00:00:00 2001
From: David Milburn <dmilburn at redhat.com>
Date: Mon, 13 Jul 2015 11:48:23 -0500
Subject: libata: add ATA_HORKAGE_MAX_SEC_1024 to revert back to previous
 max_sectors limit

commit af34d637637eabaf49406eb35c948cd51ba262a6 upstream.

Since no longer limiting max_sectors to BLK_DEF_MAX_SECTORS (commit 34b48db66e08),
data corruption may occur on ST380013AS drive configured on 82801JI (ICH10 Family)
SATA controller. This patch will allow the driver to limit max_sectors as before

 # cat /sys/block/sdb/queue/max_sectors_kb
 512

I was able to double the max_sectors_kb value up to 16384 on linux-4.2.0-rc2
before seeing corruption, but seems safer to use previous limit. Without this
patch max_sectors_kb will be 32767.

tj: Minor comment update.

Reported-by: Jeff Moyer <jmoyer at redhat.com>
Signed-off-by: David Milburn <dmilburn at redhat.com>
Signed-off-by: Tejun Heo <tj at kernel.org>
Fixes: 34b48db66e08 ("block: remove artifical max_hw_sectors cap")
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/ata/libata-core.c | 10 ++++++++++
 include/linux/ata.h       |  1 +
 include/linux/libata.h    |  2 +-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 45a4c3f..fc4d2a7 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2486,6 +2486,10 @@ int ata_dev_configure(struct ata_device *dev)
 		dev->max_sectors = min_t(unsigned int, ATA_MAX_SECTORS_128,
 					 dev->max_sectors);

+	if (dev->horkage & ATA_HORKAGE_MAX_SEC_1024)
+		dev->max_sectors = min_t(unsigned int, ATA_MAX_SECTORS_1024,
+					 dev->max_sectors);
+
 	if (dev->horkage & ATA_HORKAGE_MAX_SEC_LBA48)
 		dev->max_sectors = ATA_MAX_SECTORS_LBA48;

@@ -4154,6 +4158,12 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = {
 	{ "Slimtype DVD A  DS8A8SH", NULL,	ATA_HORKAGE_MAX_SEC_LBA48 },
 	{ "Slimtype DVD A  DS8A9SH", NULL,	ATA_HORKAGE_MAX_SEC_LBA48 },

+	/*
+	 * Causes silent data corruption with higher max sects.
+	 * http://lkml.kernel.org/g/x49wpy40ysk.fsf@segfault.boston.devel.redhat.com
+	 */
+	{ "ST380013AS",		"3.20",		ATA_HORKAGE_MAX_SEC_1024 },
+
 	/* Devices we expect to fail diagnostics */

 	/* Devices where NCQ should be avoided */
diff --git a/include/linux/ata.h b/include/linux/ata.h
index f2f4d8d..3c35318 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -45,6 +45,7 @@ enum {
 	ATA_SECT_SIZE		= 512,
 	ATA_MAX_SECTORS_128	= 128,
 	ATA_MAX_SECTORS		= 256,
+	ATA_MAX_SECTORS_1024    = 1024,
 	ATA_MAX_SECTORS_LBA48	= 65535,/* TODO: 65536? */
 	ATA_MAX_SECTORS_TAPE	= 65535,

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 0009fae..e67edef 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -432,7 +432,7 @@ enum {
 	ATA_HORKAGE_WD_BROKEN_LPM = (1 << 21),	/* some WDs have broken LPM */
 	ATA_HORKAGE_ZERO_AFTER_TRIM = (1 << 22),/* guarantees zero after trim */
 	ATA_HORKAGE_NOTRIM	= (1 << 24),	/* don't use TRIM */
-
+	ATA_HORKAGE_MAX_SEC_1024 = (1 << 25),	/* Limit max sects to 1024 */

 	 /* DMA mask for user DMA control: User visible values; DO NOT
 	    renumber */
--
1.9.1