Commit-ID: 066bb1c84aa430d15f36070471cbfe8976631cce
Gitweb: http://git.kernel.org/tip/066bb1c84aa430d15f36070471cbfe8976631cce
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Tue, 7 Mar 2017 07:30:58 -0800
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Wed, 12 Apr 2017 08:23:42 -0700
doc: Update rcu_assign_pointer() definition in whatisRCU.txt
The rcu_assign_pointer() macro has changed over time, and the version
in Documentation/RCU/whatisRCU.txt has not kept up. This commit brings
it into 2017, albeit in a simplified fashion.
Reported-by: Andrea Parri <parri.andrea@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
Documentation/RCU/whatisRCU.txt | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index 5cbd8b2..6b03370 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -587,20 +587,21 @@ It is extremely simple:
write_unlock(&rcu_gp_mutex);
}
-[You can ignore rcu_assign_pointer() and rcu_dereference() without
-missing much. But here they are anyway. And whatever you do, don't
-forget about them when submitting patches making use of RCU!]
-
- #define rcu_assign_pointer(p, v) ({ \
- smp_wmb(); \
- (p) = (v); \
- })
-
- #define rcu_dereference(p) ({ \
- typeof(p) _________p1 = p; \
- smp_read_barrier_depends(); \
- (_________p1); \
- })
+[You can ignore rcu_assign_pointer() and rcu_dereference() without missing
+much. But here are simplified versions anyway. And whatever you do,
+don't forget about them when submitting patches making use of RCU!]
+
+ #define rcu_assign_pointer(p, v) \
+ ({ \
+ smp_store_release(&(p), (v)); \
+ })
+
+ #define rcu_dereference(p) \
+ ({ \
+ typeof(p) _________p1 = p; \
+ smp_read_barrier_depends(); \
+ (_________p1); \
+ })
The rcu_read_lock() and rcu_read_unlock() primitive read-acquire
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