This patch interchanges the "if" and "else" branches of the big "if"
statement in iso_stream_schedule(), in preparation for the next patch
in this series. That is, it changes
if (likely(!...)) {
A
} else {
B
}
to
if (unlikely(...)) {
B
} else {
A
}
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
[as1706]
drivers/usb/host/ehci-sched.c | 92 +++++++++++++++++++++---------------------
1 file changed, 47 insertions(+), 45 deletions(-)
Index: usb-3.11/drivers/usb/host/ehci-sched.c
===================================================================
--- usb-3.11.orig/drivers/usb/host/ehci-sched.c
+++ usb-3.11/drivers/usb/host/ehci-sched.c
@@ -1402,12 +1402,57 @@ iso_stream_schedule (
now = ehci_read_frame_index(ehci) & (mod - 1);
- /* Typical case: reuse current schedule, stream is still active.
+ /*
+ * Need to schedule; when's the next (u)frame we could start?
+ * This is bigger than ehci->i_thresh allows; scheduling itself
+ * isn't free, the delay should handle reasonably slow cpus. It
+ * can also help high bandwidth if the dma and irq loads don't
+ * jump until after the queue is primed.
+ */
+ if (unlikely(list_empty(&stream->td_list))) {
+ int done = 0;
+
+ base = now & ~0x07;
+ start = base + SCHEDULING_DELAY;
+
+ /* find a uframe slot with enough bandwidth.
+ * Early uframes are more precious because full-speed
+ * iso IN transfers can't use late uframes,
+ * and therefore they should be allocated last.
+ */
+ next = start;
+ start += period;
+ do {
+ start--;
+ /* check schedule: enough space? */
+ if (stream->highspeed) {
+ if (itd_slot_ok(ehci, mod, start,
+ stream->usecs, period))
+ done = 1;
+ } else {
+ if ((start % 8) >= 6)
+ continue;
+ if (sitd_slot_ok(ehci, mod, stream,
+ start, sched, period))
+ done = 1;
+ }
+ } while (start > next && !done);
+
+ /* no room in the schedule */
+ if (!done) {
+ ehci_dbg(ehci, "iso sched full %p", urb);
+ status = -ENOSPC;
+ goto fail;
+ }
+ }
+
+ /*
+ * Typical case: reuse current schedule, stream is still active.
* Hopefully there are no gaps from the host falling behind
* (irq delays etc). If there are, the behavior depends on
* whether URB_ISO_ASAP is set.
*/
- if (likely (!list_empty (&stream->td_list))) {
+ else {
/* Take the isochronous scheduling threshold into account */
if (ehci->i_thresh)
@@ -1454,49 +1499,6 @@ iso_stream_schedule (
start += base;
}
- /* need to schedule; when's the next (u)frame we could start?
- * this is bigger than ehci->i_thresh allows; scheduling itself
- * isn't free, the delay should handle reasonably slow cpus. it
- * can also help high bandwidth if the dma and irq loads don't
- * jump until after the queue is primed.
- */
- else {
- int done = 0;
-
- base = now & ~0x07;
- start = base + SCHEDULING_DELAY;
-
- /* find a uframe slot with enough bandwidth.
- * Early uframes are more precious because full-speed
- * iso IN transfers can't use late uframes,
- * and therefore they should be allocated last.
- */
- next = start;
- start += period;
- do {
- start--;
- /* check schedule: enough space? */
- if (stream->highspeed) {
- if (itd_slot_ok(ehci, mod, start,
- stream->usecs, period))
- done = 1;
- } else {
- if ((start % 8) >= 6)
- continue;
- if (sitd_slot_ok(ehci, mod, stream,
- start, sched, period))
- done = 1;
- }
- } while (start > next && !done);
-
- /* no room in the schedule */
- if (!done) {
- ehci_dbg(ehci, "iso sched full %p", urb);
- status = -ENOSPC;
- goto fail;
- }
- }
-
/* Tried to schedule too far into the future? */
if (unlikely(start - base + span - period >= mod)) {
ehci_dbg(ehci, "request %p would overflow (%u+%u >= %u)\n",
--
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