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Subject[PATCH 4.13 45/85] ALSA: seq: Enable use locking in all configurations
Date
4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben.hutchings@codethink.co.uk>

commit 8009d506a1dd00cf436b0c4cca0dcec130580a21 upstream.

The 'use' locking macros are no-ops if neither SMP or SND_DEBUG is
enabled. This might once have been OK in non-preemptible
configurations, but even in that case snd_seq_read() may sleep while
relying on a 'use' lock. So always use the proper implementations.

Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/core/seq/seq_lock.c | 4 ----
sound/core/seq/seq_lock.h | 12 ------------
2 files changed, 16 deletions(-)

--- a/sound/core/seq/seq_lock.c
+++ b/sound/core/seq/seq_lock.c
@@ -23,8 +23,6 @@
#include <sound/core.h>
#include "seq_lock.h"

-#if defined(CONFIG_SMP) || defined(CONFIG_SND_DEBUG)
-
/* wait until all locks are released */
void snd_use_lock_sync_helper(snd_use_lock_t *lockp, const char *file, int line)
{
@@ -41,5 +39,3 @@ void snd_use_lock_sync_helper(snd_use_lo
}
}
EXPORT_SYMBOL(snd_use_lock_sync_helper);
-
-#endif
--- a/sound/core/seq/seq_lock.h
+++ b/sound/core/seq/seq_lock.h
@@ -3,8 +3,6 @@

#include <linux/sched.h>

-#if defined(CONFIG_SMP) || defined(CONFIG_SND_DEBUG)
-
typedef atomic_t snd_use_lock_t;

/* initialize lock */
@@ -20,14 +18,4 @@ typedef atomic_t snd_use_lock_t;
void snd_use_lock_sync_helper(snd_use_lock_t *lock, const char *file, int line);
#define snd_use_lock_sync(lockp) snd_use_lock_sync_helper(lockp, __BASE_FILE__, __LINE__)

-#else /* SMP || CONFIG_SND_DEBUG */
-
-typedef spinlock_t snd_use_lock_t; /* dummy */
-#define snd_use_lock_init(lockp) /**/
-#define snd_use_lock_use(lockp) /**/
-#define snd_use_lock_free(lockp) /**/
-#define snd_use_lock_sync(lockp) /**/
-
-#endif /* SMP || CONFIG_SND_DEBUG */
-
#endif /* __SND_SEQ_LOCK_H */

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