diff options
| author | Huacai Chen <chenhc@lemote.com> | 2017-11-21 14:23:38 +0100 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2017-11-21 23:05:57 -0500 |
| commit | 90addc6b3c9cda0146fbd62a08e234c2b224a80c (patch) | |
| tree | 7cdc0b3f4b87d26c8f91125edaea8723764526bf /drivers/scsi | |
| parent | 860dd4424f344400b491b212ee4acb3a358ba9d9 (diff) | |
| download | linux-90addc6b3c9cda0146fbd62a08e234c2b224a80c.tar.bz2 | |
scsi: use dma_get_cache_alignment() as minimum DMA alignment
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.
Cc: stable@vger.kernel.org
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>
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 1cbc497e00bd..00742c50cd44 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2148,11 +2148,13 @@ 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); } EXPORT_SYMBOL_GPL(__scsi_init_queue); |