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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 600c1e0626a5ff6c91df3a0b2f2fcf0ef485fedf..b20a2752f934f8f427d796341ed0a433f1948487 100644 (file)
--- 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];