[34-longterm 133/247] xhci: Avoid BUG() in interrupt context

Paul Gortmaker
2011-06-23T18:08:37Z

From: Paul Zimmerman <Paul.Zimmerman@synopsys.com>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

commit 68e41c5d032668e2905404afbef75bc58be179d6 upstream.

Change the BUGs in xhci_find_new_dequeue_state() to WARN_ONs, to avoid
bringing down the box if one of them is hit

This patch should be queued for stable kernels back to 2.6.31.

Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/usb/host/xhci-ring.c | 13 +++++++++----
1 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 632a7b6..6ead609 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -392,8 +392,11 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci,
state->new_deq_seg = find_trb_seg(cur_td->start_seg,
dev->eps[ep_index].stopped_trb,
&state->new_cycle_state);
- if (!state->new_deq_seg)
- BUG();
+ if (!state->new_deq_seg) {
+ WARN_ON(1);
+ return;
+ }
+
/* Dig out the cycle state saved by the xHC during the stop ep cmd */
xhci_dbg(xhci, "Finding endpoint context\n");
ep_ctx = xhci_get_ep_ctx(xhci, dev->out_ctx, ep_index);
@@ -404,8 +407,10 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci,
state->new_deq_seg = find_trb_seg(state->new_deq_seg,
state->new_deq_ptr,
&state->new_cycle_state);
- if (!state->new_deq_seg)
- BUG();
+ if (!state->new_deq_seg) {
+ WARN_ON(1);
+ return;
+ }

trb = &state->new_deq_ptr->generic;
if ((trb->field[3] & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK) &&
--
1.7.4.4