| Message ID | 1508227542-13165-3-git-send-email-chenhc@lemote.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Tue, Oct 17, 2017 at 04:05:40PM +0800, Huacai Chen wrote: > 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. Looks fine to, and I like cleaning up the arcane 0x03 as wel.
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);
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: stable@vger.kernel.org Signed-off-by: Huacai Chen <chenhc@lemote.com> --- drivers/scsi/scsi_lib.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)