Author: hselasky
Date: Sat Nov 19 11:17:27 2011
New Revision: 227706
URL: http://svn.freebsd.org/changeset/base/227706
Log:
Simplify the usb_pause_mtx() function by factoring out the generic parts
to the kernel's pause() function. The pause() function can now be used
when cold != 0. Also assert that the timeout in system ticks must be
positive.
Suggested by: Bruce Evans
MFC after: 1 week
Modified:
head/sys/dev/usb/usb_util.c
head/sys/kern/kern_synch.c
Modified: head/sys/dev/usb/usb_util.c
==============================================================================
--- head/sys/dev/usb/usb_util.c Sat Nov 19 10:49:03 2011 (r227705)
+++ head/sys/dev/usb/usb_util.c Sat Nov 19 11:17:27 2011 (r227706)
@@ -115,33 +115,21 @@ device_set_usb_desc(device_t dev)
*
* This function will delay the code by the passed number of system
* ticks. The passed mutex "mtx" will be dropped while waiting, if
- * "mtx" is not NULL.
+ * "mtx" is different from NULL.
*------------------------------------------------------------------------*/
void
-usb_pause_mtx(struct mtx *mtx, int _ticks)
+usb_pause_mtx(struct mtx *mtx, int timo)
{
if (mtx != NULL)
mtx_unlock(mtx);
- if (cold) {
- /* convert to milliseconds */
- _ticks = (_ticks * 1000) / hz;
- /* convert to microseconds, rounded up */
- _ticks = (_ticks + 1) * 1000;
- DELAY(_ticks);
-
- } else {
-
- /*
- * Add one to the number of ticks so that we don't return
- * too early!
- */
- _ticks++;
-
- if (pause("USBWAIT", _ticks)) {
- /* ignore */
- }
- }
+ /*
+ * Add one tick to the timeout so that we don't return too
+ * early! Note that pause() will assert that the passed
+ * timeout is positive and non-zero!
+ */
+ pause("USBWAIT", timo + 1);
+
if (mtx != NULL)
mtx_lock(mtx);
}
Modified: head/sys/kern/kern_synch.c
==============================================================================
--- head/sys/kern/kern_synch.c Sat Nov 19 10:49:03 2011 (r227705)
+++ head/sys/kern/kern_synch.c Sat Nov 19 11:17:27 2011 (r227706)
@@ -325,16 +325,34 @@ msleep_spin(void *ident, struct mtx *mtx
}
/*
- * pause() is like tsleep() except that the intention is to not be
- * explicitly woken up by another thread. Instead, the current thread
- * simply wishes to sleep until the timeout expires. It is
- * implemented using a dummy wait channel.
+ * pause() is almost like tsleep() except that the intention is to not
+ * be explicitly woken up by another thread. Instead, the current
+ * thread simply wishes to sleep until the timeout expires. It is
+ * implemented using a dummy wait channel. During cold bootup pause()
+ * will use the DELAY() function instead of tsleep() to wait the given
+ * number of system ticks. The passed "timo" argument must not be
+ * negative and also greater than zero.
*/
int
pause(const char *wmesg, int timo)
{
- KASSERT(timo != 0, ("pause: timeout required"));
+ KASSERT(timo > 0, ("pause: a positive and non-zero "
+ "timeout is required"));
+
+ if (cold) {
+ /*
+ * We delay one HZ at a time to avoid overflowing the
+ * DELAY() argument:
+ */
+ while (timo >= hz) {
+ DELAY(1000000);
+ timo -= hz;
+ }
+ if (timo > 0)
+ DELAY(timo * tick);
+ return (0);
+ }
return (tsleep(&pause_wchan, 0, wmesg, timo));
}
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