scsi: core: add a host / host template field for the virt boundary

This allows drivers setting it up easily instead of branching out to block
layer calls in slave_alloc, and ensures the upgraded max_segment_size
setting gets picked up by the DMA layer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Kashyap Desai < kashyap.desai@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hosts.c

@@ -462,6 +462,9 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	else
 		shost->dma_boundary = 0xffffffff;
 
+	if (sht->virt_boundary_mask)
+		shost->virt_boundary_mask = sht->virt_boundary_mask;
+
 	device_initialize(&shost->shost_gendev);
 	dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 	shost->shost_gendev.bus = &scsi_bus_type;

drivers/scsi/scsi_lib.c

@@ -1791,7 +1791,8 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
 	dma_set_seg_boundary(dev, shost->dma_boundary);
 
 	blk_queue_max_segment_size(q, shost->max_segment_size);
-	dma_set_max_seg_size(dev, shost->max_segment_size);
+	blk_queue_virt_boundary(q, shost->virt_boundary_mask);
+	dma_set_max_seg_size(dev, queue_max_segment_size(q));
 
 	/*
 	 * Set a reasonable default alignment:  The larger of 32-byte (dword),

include/scsi/scsi_host.h

@@ -369,6 +369,8 @@ struct scsi_host_template {
 	 */
 	unsigned long dma_boundary;
 
+	unsigned long virt_boundary_mask;
+
 	/*
 	 * This specifies "machine infinity" for host templates which don't
 	 * limit the transfer size.  Note this limit represents an absolute
@@ -587,6 +589,7 @@ struct Scsi_Host {
 	unsigned int max_sectors;
 	unsigned int max_segment_size;
 	unsigned long dma_boundary;
+	unsigned long virt_boundary_mask;
 	/*
 	 * In scsi-mq mode, the number of hardware queues supported by the LLD.
 	 *