@@ -1668,8 +1668,7 @@ against mishaps and misuse:
this purpose.
#. It is not necessary to use rcu_assign_pointer() when creating
linked structures that are to be published via a single external
- pointer. The RCU_INIT_POINTER() macro is provided for this task
- and also for assigning ``NULL`` pointers at runtime.
+ pointer. The RCU_INIT_POINTER() macro is provided for this task.
This not a hard-and-fast list: RCU's diagnostic capabilities will
continue to be guided by the number and type of usage bugs found in
The following commit has been merged into the core/rcu branch of tip: Commit-ID: d756c74e6f6e76e99f8bffcea57833816dd335b6 Gitweb: https://git.kernel.org/tip/d756c74e6f6e76e99f8bffcea57833816dd335b6 Author: Paul E. McKenney <paulmck@kernel.org> AuthorDate: Wed, 09 Dec 2020 16:54:41 -08:00 Committer: Paul E. McKenney <paulmck@kernel.org> CommitterDate: Mon, 04 Jan 2021 13:35:15 -08:00 doc: Update RCU requirements RCU_INIT_POINTER() description Back in the day, RCU_INIT_POINTER() was the only way to avoid memory-barrier instructions while storing NULL to an RCU-protected pointer. Fortunately, in 2016, rcu_assign_pointer() started checking for compile-time NULL pointers and omitting the memory-barrier instructions in that case. Unfortunately, RCU's Requirements.rst document was not updated accordingly. This commit therefore at long last carries out that update. Fixes: 3a37f7275cda ("rcu: No ordering for rcu_assign_pointer() of NULL") Link: https://lore.kernel.org/lkml/20201209230755.GV7338@casper.infradead.org/ Reported-by: Matthew Wilcox <willy@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- Documentation/RCU/Design/Requirements/Requirements.rst | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)