scsi: core: take the DMA max mapping size into account

We need to limit the device's 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 <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/scsi_lib.c

···
 		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);