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, 2 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 06595ec27bb7..e097008d6fb1 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -54,6 +54,8 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
         struct pci_dev          *pdev = to_pci_dev(hcd->self.controller);
         int                     retval;
 
+        hcd->self.sg_tablesize = TRBS_PER_SEGMENT - 1;
+
         xhci->cap_regs = hcd->regs;
         xhci->op_regs = hcd->regs +
                 HC_LENGTH(xhci_readl(xhci, &xhci->cap_regs->hc_capbase));