Patch "libata: Align ata_device's id on a cacheline" has been added to the 4.4-stable tree

Patch "libata: Align ata_device's id on a cacheline" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    libata: Align ata_device's id on a cacheline

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     libata-align-ata_device-s-id-on-a-cacheline.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 4ee34ea3a12396f35b26d90a094c75db95080baa Mon Sep 17 00:00:00 2001
From: Harvey Hunt <harvey.hunt@imgtec.com>
Date: Wed, 24 Feb 2016 15:16:43 +0000
Subject: libata: Align ata_device's id on a cacheline

From: Harvey Hunt <harvey.hunt@imgtec.com>

commit 4ee34ea3a12396f35b26d90a094c75db95080baa upstream.

The id buffer in ata_device is a DMA target, but it isn't explicitly
cacheline aligned. Due to this, adjacent fields can be overwritten with
stale data from memory on non coherent architectures. As a result, the
kernel is sometimes unable to communicate with an ATA device.

Fix this by ensuring that the id buffer is cacheline aligned.

This issue is similar to that fixed by Commit 84bda12af31f
("libata: align ap->sector_buf").

Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/linux/libata.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -718,7 +718,7 @@ struct ata_device {
 	union {
 		u16		id[ATA_ID_WORDS]; /* IDENTIFY xxx DEVICE data */
 		u32		gscr[SATA_PMP_GSCR_DWORDS]; /* PMP GSCR block */
-	};
+	} ____cacheline_aligned;
 
 	/* DEVSLP Timing Variables from Identify Device Data Log */
 	u8			devslp_timing[ATA_LOG_DEVSLP_SIZE];


Patches currently in stable-queue which might be from harvey.hunt@imgtec.com are

queue-4.4/libata-align-ata_device-s-id-on-a-cacheline.patch