[RFC PATCH mtd-utils 026/110] ubifs-utils: Add mutexlock implementations

[Zhihao Cheng]

Add mutexlock implementations, because there are some mutexlocks
(eg. c->tnc_mutex, c->log_mutex) used in UBIFS linux kernel libs.
The mutexlock is implementated based on pthread mutex.

This is a preparation for replacing implementation of UBIFS utils with
linux kernel libs.

Signed-off-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
---
 ubifs-utils/Makemodule.am  |  1 +
 ubifs-utils/common/mutex.h | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 ubifs-utils/common/mutex.h

diff --git a/ubifs-utils/Makemodule.am b/ubifs-utils/Makemodule.am
index 7849114e..9f33f0db 100644
--- a/ubifs-utils/Makemodule.am
+++ b/ubifs-utils/Makemodule.am
@@ -6,6 +6,7 @@ common_SOURCES = \
 	ubifs-utils/common/bitops.h \
 	ubifs-utils/common/bitops.c \
 	ubifs-utils/common/spinlock.h \
+	ubifs-utils/common/mutex.h \
 	ubifs-utils/common/kmem.h \
 	ubifs-utils/common/kmem.c \
 	ubifs-utils/common/defs.h \
diff --git a/ubifs-utils/common/mutex.h b/ubifs-utils/common/mutex.h
new file mode 100644
index 00000000..4bf018b0
--- /dev/null
+++ b/ubifs-utils/common/mutex.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_MUTEX_H_
+#define __LINUX_MUTEX_H_
+
+#include <pthread.h>
+
+struct mutex {
+	pthread_mutex_t lock;
+};
+
+#define mutex_init(x)		pthread_mutex_init(&(x)->lock, NULL)
+
+#define mutex_lock(x)		pthread_mutex_lock(&(x)->lock)
+#define mutex_lock_nested(x, c)	pthread_mutex_lock(&(x)->lock)
+#define mutex_unlock(x)		pthread_mutex_unlock(&(x)->lock)
+#define mutex_is_locked(x)	(pthread_mutex_trylock(&(x)->lock) == EBUSY)
+
+#endif
-- 
2.13.6