patch-2.4.20 linux-2.4.20/include/asm-ppc/rwsem.h
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- Lines: 45
- Date:
Thu Nov 28 15:53:15 2002
- Orig file:
linux-2.4.19/include/asm-ppc/rwsem.h
- Orig date:
Mon May 21 15:02:06 2001
diff -urN linux-2.4.19/include/asm-ppc/rwsem.h linux-2.4.20/include/asm-ppc/rwsem.h
@@ -1,5 +1,5 @@
/*
- * BK Id: SCCS/s.rwsem.h 1.6 05/17/01 18:14:25 cort
+ * BK Id: %F% %I% %G% %U% %#%
*/
/*
* include/asm-ppc/rwsem.h: R/W semaphores for PPC using the stuff
@@ -77,6 +77,20 @@
rwsem_down_read_failed(sem);
}
+static inline int __down_read_trylock(struct rw_semaphore *sem)
+{
+ int tmp;
+
+ while ((tmp = sem->count) >= 0) {
+ if (tmp == cmpxchg(&sem->count, tmp,
+ tmp + RWSEM_ACTIVE_READ_BIAS)) {
+ smp_wmb();
+ return 1;
+ }
+ }
+ return 0;
+}
+
/*
* lock for writing
*/
@@ -92,6 +106,16 @@
rwsem_down_write_failed(sem);
}
+static inline int __down_write_trylock(struct rw_semaphore *sem)
+{
+ int tmp;
+
+ tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
+ RWSEM_ACTIVE_WRITE_BIAS);
+ smp_wmb();
+ return tmp == RWSEM_UNLOCKED_VALUE;
+}
+
/*
* unlock after reading
*/
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