From ab4720ec76b756e1f8705e207a7b392b0453afd6 Mon Sep 17 00:00:00 2001 From: Dipankar Sarma Date: Mon, 12 Dec 2005 00:37:05 -0800 Subject: [PATCH] add rcu_barrier() synchronization point This introduces a new interface - rcu_barrier() which waits until all the RCUs queued until this call have been completed. Reiser4 needs this, because we do more than just freeing memory object in our RCU callback: we also remove it from the list hanging off super-block. This means, that before freeing reiser4-specific portion of super-block (during umount) we have to wait until all pending RCU callbacks are executed. The only change of reiser4 made to the original patch, is exporting of rcu_barrier(). Cc: Hans Reiser Cc: Vladimir V. Saveliev Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/rcupdate.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index cce25591eec..a471f3bb713 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -100,6 +100,7 @@ struct rcu_data { struct rcu_head *donelist; struct rcu_head **donetail; int cpu; + struct rcu_head barrier; }; DECLARE_PER_CPU(struct rcu_data, rcu_data); @@ -285,6 +286,7 @@ extern void FASTCALL(call_rcu_bh(struct rcu_head *head, extern __deprecated_for_modules void synchronize_kernel(void); extern void synchronize_rcu(void); void synchronize_idle(void); +extern void rcu_barrier(void); #endif /* __KERNEL__ */ #endif /* __LINUX_RCUPDATE_H */ -- cgit v1.2.3