On 6/17/19 5:19 AM, Christoph Hellwig wrote:
We need to limit the devices max_sectors to what the DMA mapping implementation can support. If not we risk running out of swiotlb buffers easily.Signed-off-by: Christoph Hellwig <h...@lst.de> --- drivers/scsi/scsi_lib.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index d333bb6b1c59..f233bfd84cd7 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1768,6 +1768,8 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); }+ shost->max_sectors = min_t(unsigned int, shost->max_sectors,+ dma_max_mapping_size(dev) << SECTOR_SHIFT); blk_queue_max_hw_sectors(q, shost->max_sectors); if (shost->unchecked_isa_dma) blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
Does dma_max_mapping_size() return a value in bytes? Is shost->max_sectors a number of sectors? If so, are you sure that "<< SECTOR_SHIFT" is the proper conversion? Shouldn't that be ">> SECTOR_SHIFT" instead?
Additionally, how about adding a comment above dma_max_mapping_size() that documents the unit of the returned number?
Thanks, Bart.
