Change the return value of sema_timedwait() so it returns 0 on

success and a proper errno value on failure.  This makes it
consistent with cv_timedwait(), and paves the way for the
introduction of functions such as sema_timedwait_sig() which can
fail in multiple ways.

Bump __FreeBSD_version and add a note to UPDATING.

Approved by:	scottl (ips driver), arch

5 files changed, 32 insertions, 15 deletions

diff --git a/UPDATING b/UPDATING
index e5a8042..592d429 100644
--- a/UPDATING
+++ b/UPDATING
@@ -17,6 +17,12 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 5.x IS SLOW:
 	developers choose to disable these features on build machines
 	to maximize performance.
 
+20040614:
+	The return value of sema_timedwait(9) has been changed to
+	make it consistent with cv_timedwait(9).  Be sure to recompile
+	the ips module and any third-party modules which call
+	sema_timedwait.
+
 20040613:
 	ALTQ is now linked to the build. This breaks ABI for struct ifnet.
 	Make sure to recompile modules and any userland that makes use of
diff --git a/share/man/man9/sema.9 b/share/man/man9/sema.9
index 9ba5890..e8f2cb9 100644
--- a/share/man/man9/sema.9
+++ b/share/man/man9/sema.9
@@ -98,13 +98,26 @@ argument to
 .Fn sema_timedwait
 specifies the minimum time in ticks to wait before returning with failure.
 .Fn sema_value
+is used to read the current value of the semaphore.
+.Sh RETURN VALUES
+.Fn sema_value
 returns the current value of the semaphore.
 .Pp
-.Fn sema_timedwait
-and
+If decrementing the semaphore would result in its value being negative,
 .Fn sema_trywait
-will return 0 if waiting on the semaphore failed; otherwise a non-zero value
-will be returned to indicate success.
+returns 0 to indicate failure.
+Otherwise, a non-zero value is returned to indicate success.
+.Pp
+.Fn sema_timedwait
+returns 0 if waiting on the semaphore succeeded; otherwise a
+non-zero error code is returned.
+.Sh ERRORS
+.Fn sema_timedwait
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EWOULDBLOCK
+Timeout expired.
+.El
 .Sh SEE ALSO
 .Xr condvar 9 ,
 .Xr mtx_pool 9 ,
diff --git a/sys/dev/ips/ips_commands.c b/sys/dev/ips/ips_commands.c
index d9bc5b7..e2495ab 100644
--- a/sys/dev/ips/ips_commands.c
+++ b/sys/dev/ips/ips_commands.c
@@ -248,7 +248,7 @@ static int ips_send_adapter_info_cmd(ips_command_t *command)
 			ips_adapter_info_callback, command, BUS_DMA_NOWAIT);
 
 	if ((status->value == IPS_ERROR_STATUS) ||
-	    (sema_timedwait(&command->cmd_sema, 30*hz) == 0))
+	    (sema_timedwait(&command->cmd_sema, 30*hz) != 0))
 		error = ETIMEDOUT;
 
 	if (error == 0) {
@@ -352,7 +352,7 @@ static int ips_send_drive_info_cmd(ips_command_t *command)
 			command->data_buffer,IPS_DRIVE_INFO_LEN, 
 			ips_drive_info_callback, command, BUS_DMA_NOWAIT);
 	if ((status->value == IPS_ERROR_STATUS) ||
-	    (sema_timedwait(&command->cmd_sema, 10*hz) == 0))
+	    (sema_timedwait(&command->cmd_sema, 10*hz) != 0))
 		error = ETIMEDOUT;
 
 	if (error == 0) {
@@ -606,7 +606,7 @@ static int ips_read_nvram(ips_command_t *command){
 			command->data_buffer,IPS_NVRAM_PAGE_SIZE, 
 			ips_read_nvram_callback, command, BUS_DMA_NOWAIT);
 	if ((status->value == IPS_ERROR_STATUS) ||
-	    (sema_timedwait(&command->cmd_sema, 30*hz) == 0))
+	    (sema_timedwait(&command->cmd_sema, 30*hz) != 0))
 		error = ETIMEDOUT;
 
 	if (error == 0) {
diff --git a/sys/kern/kern_sema.c b/sys/kern/kern_sema.c
index 0ee350a..f29aa88 100644
--- a/sys/kern/kern_sema.c
+++ b/sys/kern/kern_sema.c
@@ -108,7 +108,7 @@ _sema_wait(struct sema *sema, const char *file, int line)
 int
 _sema_timedwait(struct sema *sema, int timo, const char *file, int line)
 {
-	int ret, timed_out;
+	int error;
 
 	mtx_lock(&sema->sema_mtx);
 
@@ -118,27 +118,25 @@ _sema_timedwait(struct sema *sema, int timo, const char *file, int line)
 	 * continuously, since the timeout period is merely a lower bound on how
 	 * long to wait.
 	 */
-	for (timed_out = 0; sema->sema_value == 0 && timed_out == 0;) {
+	for (error = 0; sema->sema_value == 0 && error == 0;) {
 		sema->sema_waiters++;
-		timed_out = cv_timedwait(&sema->sema_cv, &sema->sema_mtx, timo);
+		error = cv_timedwait(&sema->sema_cv, &sema->sema_mtx, timo);
 		sema->sema_waiters--;
 	}
 	if (sema->sema_value > 0) {
 		/* Success. */
 		sema->sema_value--;
-		ret = 1;
+		error = 0;
 
 		CTR6(KTR_LOCK, "%s(%p) \"%s\" v = %d at %s:%d", __func__, sema,
 		    cv_wmesg(&sema->sema_cv), sema->sema_value, file, line);
 	} else {
-		ret = 0;
-		
 		CTR5(KTR_LOCK, "%s(%p) \"%s\" fail at %s:%d", __func__, sema,
 		    cv_wmesg(&sema->sema_cv), file, line);
 	}
 
 	mtx_unlock(&sema->sema_mtx);
-	return (ret);
+	return (error);
 }
 
 int
diff --git a/sys/sys/param.h b/sys/sys/param.h
index 4324e64..ad72535 100644
--- a/sys/sys/param.h
+++ b/sys/sys/param.h
@@ -55,7 +55,7 @@
  * scheme is:  <major><two digit minor><0 if release branch, otherwise 1>xx
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 502114	/* Master, propagated to newvers */
+#define __FreeBSD_version 502115	/* Master, propagated to newvers */
 
 #ifndef LOCORE
 #include <sys/types.h>