USB: make urb scatter-gather support more generic

The WHCI HCD will also support urbs with scatter-gather lists.  Add a
usb_bus field to indicated how many sg list elements are supported by
the HCD.  Use this to decide whether to pass the scatter-list to the HCD
or not.

Make the usb-storage driver use this new field.

Signed-off-by: David Vrabel <david.vrabel@csr.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 1 insertions, 7 deletions

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index e80f1af438c8..8d874cad6581 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -393,13 +393,7 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
         if (io->entries <= 0)
                 return io->entries;
 
-        /* If we're running on an xHCI host controller, queue the whole scatter
-         * gather list with one call to urb_enqueue().  This is only for bulk,
-         * as that endpoint type does not care how the data gets broken up
-         * across frames.
-         */
-        if (usb_pipebulk(pipe) &&
-                        bus_to_hcd(dev->bus)->driver->flags & HCD_USB3) {
+        if (dev->bus->sg_tablesize > 0) {
                 io->urbs = kmalloc(sizeof *io->urbs, mem_flags);
                 use_sg = true;
         } else {