Commit d6c9ea90 authored by Ben Hutchings's avatar Ben Hutchings Committed by Sarah Sharp

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: default avatarBen Hutchings <ben@decadent.org.uk>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
parent d85b277e
...@@ -3000,7 +3000,7 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring, ...@@ -3000,7 +3000,7 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
if (num_trbs >= TRBS_PER_SEGMENT) { if (num_trbs >= TRBS_PER_SEGMENT) {
xhci_err(xhci, "Too many fragments %d, max %d\n", xhci_err(xhci, "Too many fragments %d, max %d\n",
num_trbs, TRBS_PER_SEGMENT - 1); num_trbs, TRBS_PER_SEGMENT - 1);
return -ENOMEM; return -EINVAL;
} }
nop_cmd = cpu_to_le32(TRB_TYPE(TRB_TR_NOOP) | nop_cmd = cpu_to_le32(TRB_TYPE(TRB_TR_NOOP) |
......
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