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| author | Huacai Chen <chenhc@lemote.com> | 2017-11-21 16:23:38 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-03-03 18:51:32 +0300 |
| commit | d21e1a8f546f0581532a7b0d4bd29c891a04387b (patch) | |
| tree | edf73d14e3dc1ca50f336460cd7e22514d854706 /drivers/scsi | |
| parent | 9f6c2be0197ed887375538bc9f7cffa1b33ecac1 (diff) | |
| download | linux-d21e1a8f546f0581532a7b0d4bd29c891a04387b.tar.xz | |
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>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/scsi')
| -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 7e817b1f95f0..13415aec41cd 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1671,11 +1671,13 @@ struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, 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); return q; } |