Commit d6c9ea90 authored Jan 06, 2014 by Ben Hutchings Committed by Sarah Sharp Jan 08, 2014

xhci: Avoid infinite loop when sg urb requires too many trbs



Currently prepare_ring() returns -ENOMEM if the urb won't fit into a
single ring segment.  usb_sg_wait() treats this error as a temporary
condition and will keep retrying until something else goes wrong.

The number of retries should be limited in usb_sg_wait(), but also
prepare_ring() should not return an error code that suggests it might
be worth retrying.  Change it to -EINVAL.

Reported-by:  <jidanni@jidanni.org>
References: http://bugs.debian.org/733907


Fixes: 35773dac ('usb: xhci: Link TRB must not occur within a USB payload burst')
Cc: stable <stable@vger.kernel.org> # 3.12
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

parent d85b277e

drivers/usb/host/xhci-ring.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -3000,7 +3000,7 @@ static int prepare_ring(struct xhci_hcd xhci, struct xhci_ring ep_ring,
		if (num_trbs >= TRBS_PER_SEGMENT) {
		xhci_err(xhci, "Too many fragments %d, max %d\n",
		num_trbs, TRBS_PER_SEGMENT - 1);
		return -ENOMEM;
		return -EINVAL;
		}

		nop_cmd = cpu_to_le32(TRB_TYPE(TRB_TR_NOOP) \|