linux-kernel - [tip:core/rcu] rcu: Eliminate local variable signaled from force_quiescent

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <tip-f3a8b5c6aa543bd87764418d63632eb65b80e2f6@git.kernel.org>
Date:	Wed, 13 Jan 2010 10:25:36 GMT
From:	"tip-bot for Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, paulmck@...ux.vnet.ibm.com,
	hpa@...or.com, mingo@...hat.com, tglx@...utronix.de, mingo@...e.hu
Subject: [tip:core/rcu] rcu: Eliminate local variable signaled from force_quiescent_state()

Commit-ID:  f3a8b5c6aa543bd87764418d63632eb65b80e2f6
Gitweb:     http://git.kernel.org/tip/f3a8b5c6aa543bd87764418d63632eb65b80e2f6
Author:     Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
AuthorDate: Mon, 4 Jan 2010 15:09:03 -0800
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Wed, 13 Jan 2010 09:06:02 +0100

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@...ux.vnet.ibm.com>
Cc: laijs@...fujitsu.com
Cc: dipankar@...ibm.com
Cc: mathieu.desnoyers@...ymtl.ca
Cc: josh@...htriplett.org
Cc: dvhltc@...ibm.com
Cc: niv@...ibm.com
Cc: peterz@...radead.org
Cc: rostedt@...dmis.org
Cc: Valdis.Kletnieks@...edu
Cc: dhowells@...hat.com
LKML-Reference: <1262646550602-git-send-email->
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 kernel/rcutree.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 41688ff..1d8cfb1 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;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/