tree da52dc8f0f0298711ddb13259e95e88668bf8a1d
parent 90addc6b3c9cda0146fbd62a08e234c2b224a80c
author Huacai Chen <chenhc@lemote.com> 1511270619 +0100
committer Martin K. Petersen <martin.petersen@oracle.com> 1511323592 -0500

scsi: libsas: align sata_device's rps_resp on a cacheline

The rps_resp 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 SATA
device behind a SAS expander.

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

This issue is similar to that fixed by Commit 84bda12af31f93 ("libata:
align ap->sector_buf") and Commit 4ee34ea3a12396f35b26 ("libata: Align
ata_device's id on a cacheline").

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>