In non-coherent DMA mode, kernel uses cache flushing operations to
maintain I/O coherency, so scsi's block queue should be aligned to
ARCH_DMA_MINALIGN. 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: sta...@vger.kernel.org
Signed-off-by: Huacai Chen <che...@lemote.com>
---
drivers/scsi/scsi_lib.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9cf6a80..19abc2e 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2132,11 +2132,11 @@ 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
+ * set a reasonable default alignment on word/cacheline boundaries:
+ * the host and device may alter it using
* blk_queue_update_dma_alignment() later.
*/
- blk_queue_dma_alignment(q, 0x03);
+ blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment(dev)) - 1);
}
EXPORT_SYMBOL_GPL(__scsi_init_queue);
--
2.7.0
