xref: /linux/sound/core/seq/seq_lock.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
1 /*
2  *  Do sleep inside a spin-lock
3  *  Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de>
4  *
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <linux/export.h>
23 #include <sound/core.h>
24 #include "seq_lock.h"
25 
26 #if defined(CONFIG_SMP) || defined(CONFIG_SND_DEBUG)
27 
28 /* wait until all locks are released */
29 void snd_use_lock_sync_helper(snd_use_lock_t *lockp, const char *file, int line)
30 {
31 	int warn_count = 5 * HZ;
32 
33 	if (atomic_read(lockp) < 0) {
34 		pr_warn("ALSA: seq_lock: lock trouble [counter = %d] in %s:%d\n", atomic_read(lockp), file, line);
35 		return;
36 	}
37 	while (atomic_read(lockp) > 0) {
38 		if (warn_count-- == 0)
39 			pr_warn("ALSA: seq_lock: waiting [%d left] in %s:%d\n", atomic_read(lockp), file, line);
40 		schedule_timeout_uninterruptible(1);
41 	}
42 }
43 
44 EXPORT_SYMBOL(snd_use_lock_sync_helper);
45 
46 #endif
47