[PATCH tip/core/rcu 4/5] rcu: Fix precedence error in cpu_needs_another_gp()

From: Paul E. McKenney
Date: Tue Oct 30 2012 - 13:33:00 EST


From: "Paul E. McKenney" <paul.mckenney@xxxxxxxxxx>

The fix introduced by a10d206e (rcu: Fix day-one dyntick-idle
stall-warning bug) has a C-language precedence error. It turns out
that this error is harmless in that the same result is computed for all
inputs, but the code is nevertheless a potential source of confusion.
This commit therefore introduces parentheses in order to force the
execution of the code to reflect the intent.

Reported-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcutree.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index f9c17c3..effd47a 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -313,7 +313,7 @@ static int
cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp)
{
return *rdp->nxttail[RCU_DONE_TAIL +
- ACCESS_ONCE(rsp->completed) != rdp->completed] &&
+ (ACCESS_ONCE(rsp->completed) != rdp->completed)] &&
!rcu_gp_in_progress(rsp);
}

--
1.7.8

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