mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-03 15:47:36 +00:00
8f32543b61
This commit adds comments to the litmus tests summarizing what these tests are intended to demonstrate. [ paulmck: Apply Andrea's and Alan's feedback. ] Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: nborisov@suse.com Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Cc: stern@rowland.harvard.edu Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1519169112-20593-4-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
34 lines
555 B
Text
34 lines
555 B
Text
C MP+onceassign+derefonce
|
|
|
|
(*
|
|
* Result: Never
|
|
*
|
|
* This litmus test demonstrates that rcu_assign_pointer() and
|
|
* rcu_dereference() suffice to ensure that an RCU reader will not see
|
|
* pre-initialization garbage when it traverses an RCU-protected data
|
|
* structure containing a newly inserted element.
|
|
*)
|
|
|
|
{
|
|
y=z;
|
|
z=0;
|
|
}
|
|
|
|
P0(int *x, int **y)
|
|
{
|
|
WRITE_ONCE(*x, 1);
|
|
rcu_assign_pointer(*y, x);
|
|
}
|
|
|
|
P1(int *x, int **y)
|
|
{
|
|
int *r0;
|
|
int r1;
|
|
|
|
rcu_read_lock();
|
|
r0 = rcu_dereference(*y);
|
|
r1 = READ_ONCE(*r0);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
exists (1:r0=x /\ 1:r1=0)
|