patch-2.4.20 linux-2.4.20/include/linux/rwsem.h

• Lines: 47
• Date: Thu Nov 28 15:53:15 2002
• Orig file: linux-2.4.19/include/linux/rwsem.h
• Orig date: Thu Nov 22 11:46:19 2001

diff -urN linux-2.4.19/include/linux/rwsem.h linux-2.4.20/include/linux/rwsem.h
@@ -2,6 +2,8 @@
  *
  * Written by David Howells (dhowells@redhat.com).
  * Derived from asm-i386/semaphore.h
+ *
+ * Trylock by Brian Watson (Brian.J.Watson@compaq.com).
  */
 
 #ifndef _LINUX_RWSEM_H
@@ -46,6 +48,18 @@
 }
 
 /*
+ * trylock for reading -- returns 1 if successful, 0 if contention
+ */
+static inline int down_read_trylock(struct rw_semaphore *sem)
+{
+	int ret;
+	rwsemtrace(sem,"Entering down_read_trylock");
+	ret = __down_read_trylock(sem);
+	rwsemtrace(sem,"Leaving down_read_trylock");
+	return ret;
+}
+
+/*
  * lock for writing
  */
 static inline void down_write(struct rw_semaphore *sem)
@@ -56,6 +70,18 @@
 }
 
 /*
+ * trylock for writing -- returns 1 if successful, 0 if contention
+ */
+static inline int down_write_trylock(struct rw_semaphore *sem)
+{
+	int ret;
+	rwsemtrace(sem,"Entering down_write_trylock");
+	ret = __down_write_trylock(sem);
+	rwsemtrace(sem,"Leaving down_write_trylock");
+	return ret;
+}
+
+/*
  * release a read lock
  */
 static inline void up_read(struct rw_semaphore *sem)