[Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <address@hidden>

RCU_READ_LOCK_AUTO takes the rcu_read_lock  and then uses glib's
g_auto infrastrcture (and thus whatever the compilers hooks are) to
release it on all exits of the block.

Note this macro has a variable declaration in, and hence is not in
a while loop.

Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
 include/qemu/rcu.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h
index 22876d1428..6a25b27d28 100644
--- a/include/qemu/rcu.h
+++ b/include/qemu/rcu.h
@@ -154,6 +154,18 @@ extern void call_rcu1(struct rcu_head *head, RCUCBFunc 
*func);
       }),                                                                \
       (RCUCBFunc *)g_free);
 
+typedef char rcu_read_auto_t;
+static inline void rcu_read_auto_unlock(rcu_read_auto_t *r)
+{
+  rcu_read_unlock();
+}
+
+G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(rcu_read_auto_t, rcu_read_auto_unlock)
+
+#define RCU_READ_LOCK_AUTO g_auto(rcu_read_auto_t) \
+    _rcu_read_auto = 'x'; \
+    rcu_read_lock();
+
 #ifdef __cplusplus
 }
 #endif
-- 
2.21.0