ubifs-utils: Add rwsem implementations

Add rwsem implementations, because there are some rwsems
(eg. c->commit_sem) used in UBIFS linux kernel libs.
The rwsem is implemented based on pthread mutex.

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

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

diff --git a/ubifs-utils/Makemodule.am b/ubifs-utils/Makemodule.am
index 9f33f0dbf03bb7f56373c54c9f4435dbb557d03a..ece8a6e97f0337c8374b8d7dad9fe83eb2ff7841 100644 (file)
--- a/ubifs-utils/Makemodule.am
+++ b/ubifs-utils/Makemodule.am
@@ -7,6 +7,7 @@ common_SOURCES = \
        ubifs-utils/common/bitops.c \
        ubifs-utils/common/spinlock.h \
        ubifs-utils/common/mutex.h \
+       ubifs-utils/common/rwsem.h \
        ubifs-utils/common/kmem.h \
        ubifs-utils/common/kmem.c \
        ubifs-utils/common/defs.h \

diff --git a/ubifs-utils/common/rwsem.h b/ubifs-utils/common/rwsem.h
new file mode 100644 (file)
index 0000000..3761724
--- /dev/null
+++ b/ubifs-utils/common/rwsem.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_RWSEM_H_
+#define __LINUX_RWSEM_H_
+
+#include <pthread.h>
+
+struct rw_semaphore {
+       pthread_mutex_t lock;
+};
+
+#define init_rwsem(x)                  pthread_mutex_init(&(x)->lock, NULL)
+
+#define down_read(x)                   pthread_mutex_lock(&(x)->lock)
+#define down_write(x)                  pthread_mutex_lock(&(x)->lock)
+#define up_read(x)                     pthread_mutex_unlock(&(x)->lock)
+#define up_write(x)                    pthread_mutex_unlock(&(x)->lock)
+#define down_write_trylock(x)          (pthread_mutex_trylock(&(x)->lock) == 0)
+
+#endif