[PATCH][for 4.14] xhci: allow TRACE to work with EVENT ring dequeue
From: Adam Wallis <hidden>
Date: 2017-09-22 17:20:59
Subsystem:
the rest, usb subsystem, usb xhci driver · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Mathias Nyman
inc_deq() currently bails earlier for EVENT rings than the common return point of the function, due to the fact that EVENT rings do not have link TRBs. The unfortunate side effect of this is that the very useful trace_xhci_inc_deq() function is not called/usable for EVENT ring debug. This patch provides a refactor by removing the multiple return exit points into a single return which additionally allows for all rings to use the trace function. Signed-off-by: Adam Wallis <redacted> --- drivers/usb/host/xhci-ring.c | 33 ++++++++++++++++----------------- 1 file changed, 16 insertions(+), 17 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index a944365..10afd50 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c@@ -171,25 +171,24 @@ static void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring) if (ring->type == TYPE_EVENT) { if (!last_trb_on_seg(ring->deq_seg, ring->dequeue)) { ring->dequeue++; - return; + } else { + if (last_trb_on_ring(ring, ring->deq_seg, + ring->dequeue)) + ring->cycle_state ^= 1; + ring->deq_seg = ring->deq_seg->next; + ring->dequeue = ring->deq_seg->trbs; + } + } else { + /* All other rings have link trbs */ + if (!trb_is_link(ring->dequeue)) { + ring->dequeue++; + ring->num_trbs_free++; + } + while (trb_is_link(ring->dequeue)) { + ring->deq_seg = ring->deq_seg->next; + ring->dequeue = ring->deq_seg->trbs; } - if (last_trb_on_ring(ring, ring->deq_seg, ring->dequeue)) - ring->cycle_state ^= 1; - ring->deq_seg = ring->deq_seg->next; - ring->dequeue = ring->deq_seg->trbs; - return; - } - - /* All other rings have link trbs */ - if (!trb_is_link(ring->dequeue)) { - ring->dequeue++; - ring->num_trbs_free++; - } - while (trb_is_link(ring->dequeue)) { - ring->deq_seg = ring->deq_seg->next; - ring->dequeue = ring->deq_seg->trbs; } - trace_xhci_inc_deq(ring); return;
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