Minor change to alarm_handler to avoid code duplication

[Anders Blomdell <anders.blomdell@control.lth.se>]

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As per request from discussions in
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=241780
a patch against git.

Best regards

Anders Blomdell

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--- autofs/lib/alarm.c	2007-06-07 15:05:03.000000000 +0200
+++ /usr/src/autofs/autofs.patched/lib/alarm.c	2007-06-07 15:08:29.000000000 +0200
@@ -28,16 +28,16 @@
 
 #define alarm_lock() \
 do { \
-	int _alm_lock = pthread_mutex_lock(&mutex); \
-	if (_alm_lock) \
-		fatal(_alm_lock); \
+	int status = pthread_mutex_lock(&mutex); \
+	if (status) \
+		fatal(status); \
 } while (0)
 
 #define alarm_unlock() \
 do { \
-	int _alm_unlock = pthread_mutex_unlock(&mutex); \
-	if (_alm_unlock) \
-		fatal(_alm_unlock); \
+	int status = pthread_mutex_unlock(&mutex); \
+	if (status) \
+		fatal(status); \
 } while (0)
 
 void dump_alarms(void)
@@ -168,87 +168,65 @@
 static void *alarm_handler(void *arg)
 {
 	struct list_head *head;
-	struct timespec expire;
-	time_t now;
 	int status;
-
+	
 	alarm_lock();
 
 	head = &alarms;
 
 	while (1) {
-		struct alarm *current;
-
-		/*
-		 * If the alarm list is empty, wait until an alarm is
-		 * added.
-		 */
-		while (list_empty(head)) {
+		if (list_empty(head)) {
+			/* No alarms, wait for one to be added */
 			status = pthread_cond_wait(&cond, &mutex);
 			if (status)
 				fatal(status);
-		}
-
-		current = list_entry(head->next, struct alarm, list);
-
-		now = time(NULL);
-
-		if (current->time <= now) {
-			struct autofs_point *ap;
-
-			list_del(&current->list);
-
-			if (current->cancel) {
-				free(current);
-				continue;
-			}
-
-			ap = current->ap;
-			free(current);
-			alarm_unlock();
-
-			state_mutex_lock(ap);
-			nextstate(ap->state_pipe[1], ST_EXPIRE);
-			state_mutex_unlock(ap);
-
-			alarm_lock();
-			continue;
-		}
-
-		expire.tv_sec = current->time;
-		expire.tv_nsec = 0;
-
-		while (1) {
-			struct autofs_point *ap;
-			struct alarm *next;
-
-			status = pthread_cond_timedwait(&cond, &mutex, &expire);
-			if (status && status != ETIMEDOUT)
-				fatal(status);
-
-			next = list_entry(head->next, struct alarm, list);
-			if (next->cancel) {
-				list_del(&next->list);
-				free(next);
-				break;
+		} else {
+			struct alarm *first;
+			time_t now;
+
+			first = list_entry(head->next, struct alarm, list);
+
+			now = time(NULL);
+
+			if (first->time > now) {
+				/* Wait for alarm to trigger or a new alarm 
+				   to be added */
+				struct timespec expire;
+
+				expire.tv_sec = first->time;
+				expire.tv_nsec = 0;
+
+				status = pthread_cond_timedwait(&cond, &mutex,
+								&expire);
+				if (status && status != ETIMEDOUT)
+					fatal(status);
+			} else {
+				/* First alarm has triggered, run it */
+				struct autofs_point *ap;
+
+				list_del(&first->list);
+				ap = first->ap;
+				if (!first->cancel) {
+					/* We need to unlock the alarm list 
+					   in case some other thread holds 
+					   the state_mutex_lock(ap), and is 
+					   currently trying to do some 
+					   alarm_* function (i.e if we don't 
+					   unlock, we might deadlock) */
+					alarm_unlock(); 
+
+					state_mutex_lock(ap);
+					nextstate(ap->state_pipe[1], 
+						  ST_EXPIRE);
+					state_mutex_unlock(ap);
+
+					alarm_lock();
+				}
+				free(first);
 			}
-
-			if (next != current)
-				break;
-
-			list_del(&current->list);
-			ap = current->ap;
-			free(current);
-			alarm_unlock();
-
-			state_mutex_lock(ap);
-			nextstate(ap->state_pipe[1], ST_EXPIRE);
-			state_mutex_unlock(ap);
-
-			alarm_lock();
-			break;
 		}
 	}
+	/* Will never come here, so alarm_unlock is not necessary */
 }
 
 int alarm_start_handler(void)

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