rcu: Fix precedence error in cpu_needs_another_gp()

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@decadent.org.uk>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index f9c17c3..effd47a 100644 (file)
--- 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);
 }