[PATCH 13/13] uas: set virt_boundary_mask in the scsi host
From: Christoph Hellwig
Date: Wed Jun 05 2019 - 15:13:42 EST
This ensures all proper DMA layer handling is taken care of by the
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
drivers/usb/storage/uas.c | 36 ++++++++++++++++--------------------
1 file changed, 16 insertions(+), 20 deletions(-)
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 047c5922618f..d20919e7bbf4 100644
@@ -789,29 +789,9 @@ static int uas_slave_alloc(struct scsi_device *sdev)
struct uas_dev_info *devinfo =
(struct uas_dev_info *)sdev->host->hostdata;
- int maxp;
sdev->hostdata = devinfo;
- * We have two requirements here. We must satisfy the requirements
- * of the physical HC and the demands of the protocol, as we
- * definitely want no additional memory allocation in this path
- * ruling out using bounce buffers.
- * For a transmission on USB to continue we must never send
- * a package that is smaller than maxpacket. Hence the length of each
- * scatterlist element except the last must be divisible by the
- * Bulk maxpacket value.
- * If the HC does not ensure that through SG,
- * the upper layer must do that. We must assume nothing
- * about the capabilities off the HC, so we use the most
- * pessimistic requirement.
- maxp = usb_maxpacket(devinfo->udev, devinfo->data_in_pipe, 0);
- blk_queue_virt_boundary(sdev->request_queue, maxp - 1);
* The protocol has no requirements on alignment in the strict sense.
* Controllers may or may not have alignment restrictions.
@@ -1004,6 +984,22 @@ static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
shost->can_queue = devinfo->qdepth - 2;
+ * We have two requirements here. We must satisfy the requirements of
+ * the physical HC and the demands of the protocol, as we definitely
+ * want no additional memory allocation in this path ruling out using
+ * bounce buffers.
+ * For a transmission on USB to continue we must never send a package
+ * that is smaller than maxpacket. Hence the length of each scatterlist
+ * element except the last must be divisible by the Bulk maxpacket
+ * value. If the HC does not ensure that through SG, the upper layer
+ * must do that. We must assume nothing about the capabilities off the
+ * HC, so we use the most pessimistic requirement.
+ shost->virt_boundary_mask =
+ usb_maxpacket(udev, devinfo->data_in_pipe, 0) - 1;
result = scsi_add_host(shost, &intf->dev);