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USB: EHCI: code rearrangement in iso_stream_schedule() 

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@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern 2013-09-03 13:58:59 -04:00 committed by Greg Kroah-Hartman
parent c7ccde6eac
commit e4e18cbd52
1 changed files with 47 additions and 45 deletions
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92
drivers/usb/host/ehci-sched.c
View File

@ -1384,12 +1384,57 @@ 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)
@ -1436,49 +1481,6 @@ 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",