Commit 5b91dfe1 authored Apr 18, 2016 by Felipe Balbi Committed by Greg Kroah-Hartman Apr 26, 2016

usb: storage: scsiglue: limit USB3 devices to 2048 sectors



USB3 devices, because they are much newer, have much
less chance of having issues with larger transfers.

We still keep a limit because anything above 2048
sectors really rendered negligible speed
improvements, so we will simply ignore
that. Transferring 1MiB should already give us
pretty good performance.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 779b457f

drivers/usb/storage/scsiglue.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -133,6 +133,11 @@ static int slave_configure(struct scsi_device *sdev)
		* let the queue segment size sort out the real limit.
		*/
		blk_queue_max_hw_sectors(sdev->request_queue, 0x7FFFFF);
		} else if (us->pusb_dev->speed >= USB_SPEED_SUPER) {
		/* USB3 devices will be limited to 2048 sectors. This gives us
		* better throughput on most devices.
		*/
		blk_queue_max_hw_sectors(sdev->request_queue, 2048);
		}

		/* Some USB host controllers can't do DMA; they have to use PIO.