[PATCH 2/8] scsi: take the DMA max mapping size into account

[Christoph Hellwig]

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 <hch@xxxxxx>
---
 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);
-- 
2.20.1