From: Harvey Hunt <harvey.hunt@imgtec.com>
Date: Wed, 24 Feb 2016 15:16:43 +0000 (+0000)
Subject: libata: Align ata_device's id on a cacheline
X-Git-Tag: v3.2.79~23
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=2d5a6d0db3c83f5883b542fd3f79a2a80d319b14

libata: Align ata_device's id on a cacheline

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: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 000434ef6fff..10f56437ae4d 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -662,7 +662,7 @@ struct ata_device {
 	union {
 		u16		id[ATA_ID_WORDS]; /* IDENTIFY xxx DEVICE data */
 		u32		gscr[SATA_PMP_GSCR_DWORDS]; /* PMP GSCR block */
-	};
+	} ____cacheline_aligned;
 
 	/* error history */
 	int			spdn_cnt;