[PATCH v5 03/45] percpu_rwlock: Provide a way to define and init percpu-rwlocks at compile time

[Srivatsa S. Bhat]

Add the support for defining and initializing percpu-rwlocks at compile time
for those users who would like to use percpu-rwlocks really early in the boot
process (even before dynamic per-CPU allocations can begin).

Cc: David Howells <dhowells at redhat.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat at linux.vnet.ibm.com>
---

 include/linux/percpu-rwlock.h |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/include/linux/percpu-rwlock.h b/include/linux/percpu-rwlock.h
index cd5eab5..8dec8fe 100644
--- a/include/linux/percpu-rwlock.h
+++ b/include/linux/percpu-rwlock.h
@@ -45,6 +45,24 @@ extern int __percpu_init_rwlock(struct percpu_rwlock *,
 
 extern void percpu_free_rwlock(struct percpu_rwlock *);
 
+
+#define __PERCPU_RWLOCK_INIT(name)					\
+	{								\
+		.reader_refcnt = &name##_reader_refcnt,			\
+		.writer_signal = &name##_writer_signal,			\
+		.global_rwlock = __RW_LOCK_UNLOCKED(name.global_rwlock) \
+	}
+
+#define DEFINE_PERCPU_RWLOCK(name)					\
+	static DEFINE_PER_CPU(unsigned long, name##_reader_refcnt);	\
+	static DEFINE_PER_CPU(bool, name##_writer_signal);		\
+	struct percpu_rwlock (name) = __PERCPU_RWLOCK_INIT(name);
+
+#define DEFINE_STATIC_PERCPU_RWLOCK(name)				\
+	static DEFINE_PER_CPU(unsigned long, name##_reader_refcnt);	\
+	static DEFINE_PER_CPU(bool, name##_writer_signal);		\
+	static struct percpu_rwlock(name) = __PERCPU_RWLOCK_INIT(name);
+
 #define percpu_init_rwlock(pcpu_rwlock)					\
 ({	static struct lock_class_key rwlock_key;			\
 	__percpu_init_rwlock(pcpu_rwlock, #pcpu_rwlock, &rwlock_key);	\