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    Subject[PATCH 3.2 40/62] libata: Align ata_device's id on a cacheline
    3.2.79-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    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: Ben Hutchings <ben@decadent.org.uk>
    ---
    include/linux/libata.h | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- 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;
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