linux-kernel - [tip:locking/core] locking/mutex: Simplify some ww_mutex code in __mutex_lock

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Date:   Tue, 25 Oct 2016 03:29:10 -0700
From:   tip-bot for Waiman Long <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     dingtianhong@...wei.com, tglx@...utronix.de, jason.low2@....com,
        paulmck@...ux.vnet.ibm.com, tim.c.chen@...ux.intel.com,
        paulmck@...ibm.com, akpm@...ux-foundation.org,
        linux-kernel@...r.kernel.org, dave@...olabs.net, hpa@...or.com,
        imre.deak@...el.com, torvalds@...ux-foundation.org,
        Will.Deacon@....com, mingo@...nel.org, peterz@...radead.org,
        Waiman.Long@....com
Subject: [tip:locking/core] locking/mutex: Simplify some ww_mutex code in
 __mutex_lock_common()

Commit-ID:  a40ca56577f628eb3f7af22b484e95edfdd047a2
Gitweb:     http://git.kernel.org/tip/a40ca56577f628eb3f7af22b484e95edfdd047a2
Author:     Waiman Long <Waiman.Long@....com>
AuthorDate: Fri, 26 Aug 2016 19:35:08 -0400
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 25 Oct 2016 11:31:53 +0200

locking/mutex: Simplify some ww_mutex code in __mutex_lock_common()

This patch removes some of the redundant ww_mutex code in
__mutex_lock_common().

Tested-by: Jason Low <jason.low2@....com>
Signed-off-by: Waiman Long <Waiman.Long@....com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Davidlohr Bueso <dave@...olabs.net>
Cc: Ding Tianhong <dingtianhong@...wei.com>
Cc: Imre Deak <imre.deak@...el.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@...ibm.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Tim Chen <tim.c.chen@...ux.intel.com>
Cc: Will Deacon <Will.Deacon@....com>
Link: http://lkml.kernel.org/r/1472254509-27508-1-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 kernel/locking/mutex.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 8bb2304..6c0d304 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -587,10 +587,11 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 	struct mutex_waiter waiter;
 	unsigned long flags;
 	bool first = false;
+	struct ww_mutex *ww;
 	int ret;
 
 	if (use_ww_ctx) {
-		struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+		ww = container_of(lock, struct ww_mutex, base);
 		if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
 			return -EALREADY;
 	}
@@ -602,12 +603,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 	    mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx)) {
 		/* got the lock, yay! */
 		lock_acquired(&lock->dep_map, ip);
-		if (use_ww_ctx) {
-			struct ww_mutex *ww;
-			ww = container_of(lock, struct ww_mutex, base);
-
+		if (use_ww_ctx)
 			ww_mutex_set_context_fastpath(ww, ww_ctx);
-		}
 		preempt_enable();
 		return 0;
 	}
@@ -691,10 +688,8 @@ skip_wait:
 	/* got the lock - cleanup and rejoice! */
 	lock_acquired(&lock->dep_map, ip);
 
-	if (use_ww_ctx) {
-		struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+	if (use_ww_ctx)
 		ww_mutex_set_context_slowpath(ww, ww_ctx);
-	}
 
 	spin_unlock_mutex(&lock->wait_lock, flags);
 	preempt_enable();