diff options
| author | Huacai Chen <chenhc@lemote.com> | 2017-11-21 14:23:38 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-14 09:28:11 +0100 |
| commit | 326ebe77f0c584e1de142c788f61b447bcd170b3 (patch) | |
| tree | 6aaa657ee23cdfbdb29d7cf6e6ffa75a20510d7a /drivers | |
| parent | 4cb4d78c57f8ba642b5071d439d71217291d9e71 (diff) | |
scsi: use dma_get_cache_alignment() as minimum DMA alignment
commit 90addc6b3c9cda0146fbd62a08e234c2b224a80c upstream.
In non-coherent DMA mode, kernel uses cache flushing operations to
maintain I/O coherency, so scsi's block queue should be aligned to the
value returned by dma_get_cache_alignment(). Otherwise, If a DMA buffer
and a kernel structure share a same cache line, and if the kernel
structure has dirty data, cache_invalidate (no writeback) will cause
data corruption.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
[hch: rebased and updated the comment and changelog]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index d8099c7cab00..c7b770075caa 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2041,11 +2041,13 @@ static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) q->limits.cluster = 0; /* - * set a reasonable default alignment on word boundaries: the - * host and device may alter it using - * blk_queue_update_dma_alignment() later. + * Set a reasonable default alignment: The larger of 32-byte (dword), + * which is a common minimum for HBAs, and the minimum DMA alignment, + * which is set by the platform. + * + * Devices that require a bigger alignment can increase it later. */ - blk_queue_dma_alignment(q, 0x03); + blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1); } struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, |