From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com,
bobby.prani@gmail.com,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 6/9] doc: Update rcu_assign_pointer() definition in whatisRCU.txt
Date: Wed, 12 Apr 2017 09:40:19 -0700 [thread overview]
Message-ID: <1492015222-16373-6-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170412163956.GA15691@linux.vnet.ibm.com>
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@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
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 5cbd8b2395b8..6b0337008f9c 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
--
2.5.2
next prev parent reply other threads:[~2017-04-12 16:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-12 16:39 [PATCH tip/core/rcu 0/9] Documentation updates for 4.12 Paul E. McKenney
2017-04-12 16:40 ` [PATCH tip/core/rcu 1/9] doc: Synchronous RCU grace periods are now legal throughout boot Paul E. McKenney
2017-04-13 9:07 ` Peter Zijlstra
2017-04-13 15:56 ` Paul E. McKenney
2017-04-12 16:40 ` [PATCH tip/core/rcu 2/9] doc: Add mid-boot operation to expedited grace periods Paul E. McKenney
2017-04-12 16:40 ` [PATCH tip/core/rcu 3/9] doc: Update stallwarn.txt to make causes more prominent Paul E. McKenney
2017-04-12 16:40 ` [PATCH tip/core/rcu 4/9] doc: Update RCU data-structure documentation for rcu_segcblist Paul E. McKenney
2017-04-12 16:40 ` [PATCH tip/core/rcu 5/9] doc: Update requirements based on recent changes Paul E. McKenney
2017-04-12 16:40 ` Paul E. McKenney [this message]
2017-04-12 16:40 ` [PATCH tip/core/rcu 7/9] doc: Update the comparisons rule in rcu_dereference.txt Paul E. McKenney
2017-04-12 16:40 ` [PATCH tip/core/rcu 8/9] doc: Emphasize that "toy" RCU requires recursive rwlock Paul E. McKenney
2017-04-12 16:40 ` [PATCH tip/core/rcu 9/9] doc: Update control-dependencies section of memory-barriers.txt Paul E. McKenney
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