rcu: Eliminate local variable signaled from force_quiescent_state()

Because the root rcu_node lock is held across entry to the
switch statement in force_quiescent_state(), it is no longer
necessary to snapshot rsp->signaled to a local variable.
Eliminate both the snapshotting and the local variable.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1262646550602-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 6 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 41688ff60e07..1d8cfb1711fd 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1193,7 +1193,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
         unsigned long flags;
         long lastcomp;
         struct rcu_node *rnp = rcu_get_root(rsp);
-        u8 signaled;
         u8 forcenow;
         u8 gpdone;
 
@@ -1209,7 +1208,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
         rsp->n_force_qs++;
         spin_lock(&rnp->lock);  /* irqs already disabled */
         lastcomp = rsp->gpnum - 1;
-        signaled = rsp->signaled;
         rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
         if(!rcu_gp_in_progress(rsp)) {
                 rsp->n_force_qs_ngp++;
@@ -1217,7 +1215,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
                 goto unlock_fqs_ret;  /* no GP in progress, time updated. */
         }
         rsp->fqs_active = 1;
-        switch (signaled) {
+        switch (rsp->signaled) {
         case RCU_GP_IDLE:
         case RCU_GP_INIT:
 
@@ -1242,11 +1240,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
                 /* Update state, record completion counter. */
                 forcenow = 0;
                 if (lastcomp + 1 == rsp->gpnum &&
-                    lastcomp == rsp->completed &&
-                    rsp->signaled == signaled) {
+                    lastcomp == rsp->completed) {
+                        forcenow = rsp->signaled == RCU_SAVE_COMPLETED;
                         rsp->signaled = RCU_FORCE_QS;
                         rsp->completed_fqs = lastcomp;
-                        forcenow = signaled == RCU_SAVE_COMPLETED;
                 }
                 if (!forcenow)
                         break;