path: root/include/asm-generic/mutex-null.h
diff options
authorIngo Molnar <mingo@elte.hu>2006-01-09 15:59:17 -0800
committerIngo Molnar <mingo@hera.kernel.org>2006-01-09 15:59:17 -0800
commit620a6fd185c084aa617c411f711533f01ea673c9 (patch)
tree3ab1a296a2cd952bc3dd602fc5dd2ada9288b2c4 /include/asm-generic/mutex-null.h
parent711a660dc2064013a2b0167ee67389707fc9cac3 (diff)
[PATCH] mutex subsystem, add asm-generic/mutex-[dec|xchg|null].h implementations
Add three (generic) mutex fastpath implementations. The mutex-xchg.h implementation is atomic_xchg() based, and should work fine on every architecture. The mutex-dec.h implementation is atomic_dec_return() based - this one too should work on every architecture, but might not perform the most optimally on architectures that have no atomic-dec/inc instructions. The mutex-null.h implementation forces all calls into the slowpath. This is used for mutex debugging, but it can also be used on platforms that do not want (or need) a fastpath at all. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Diffstat (limited to 'include/asm-generic/mutex-null.h')
1 files changed, 24 insertions, 0 deletions
diff --git a/include/asm-generic/mutex-null.h b/include/asm-generic/mutex-null.h
new file mode 100644
index 000000000000..5cf8b7ce0c45
--- /dev/null
+++ b/include/asm-generic/mutex-null.h
@@ -0,0 +1,24 @@
+ * asm-generic/mutex-null.h
+ *
+ * Generic implementation of the mutex fastpath, based on NOP :-)
+ *
+ * This is used by the mutex-debugging infrastructure, but it can also
+ * be used by architectures that (for whatever reason) want to use the
+ * spinlock based slowpath.
+ */
+/* extra parameter only needed for mutex debugging: */
+#ifndef __IP__
+# define __IP__
+#define __mutex_fastpath_lock(count, fail_fn) fail_fn(count __RET_IP__)
+#define __mutex_fastpath_lock_retval(count, fail_fn) fail_fn(count __RET_IP__)
+#define __mutex_fastpath_unlock(count, fail_fn) fail_fn(count __RET_IP__)
+#define __mutex_fastpath_trylock(count, fail_fn) fail_fn(count)
+#define __mutex_slowpath_needs_to_unlock() 1