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@hpe.com>
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ding Tianhong <dingtianhong@huawei.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Will Deacon <Will.Deacon@arm.com>
Link: http://lkml.kernel.org/r/1472254509-27508-1-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 8bb2304bb78db627f1d05599e926d6cce454a227..6c0d3040e4dc369e9077eaf2d744374a4204d1ba 100644 (file)
--- 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();