1 files changed, 21 insertions, 30 deletions

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 94674e5919cb..4cccea6b8934 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -25,7 +25,7 @@
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/debug_locks.h>
-#include "mcs_spinlock.h"
+#include <linux/osq_lock.h>
 
 /*
  * In the DEBUG case we are using the "NULL fastpath" for mutexes,
@@ -217,44 +217,35 @@ ww_mutex_set_context_slowpath(struct ww_mutex *lock,
 }
 
 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
-{
-        if (lock->owner != owner)
-                return false;
-
-        /*
-         * Ensure we emit the owner->on_cpu, dereference _after_ checking
-         * lock->owner still matches owner, if that fails, owner might
-         * point to free()d memory, if it still matches, the rcu_read_lock()
-         * ensures the memory stays valid.
-         */
-        barrier();
-
-        return owner->on_cpu;
-}
-
 /*
  * Look out! "owner" is an entirely speculative pointer
  * access and not reliable.
  */
 static noinline
-int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
+bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
 {
+        bool ret = true;
+
         rcu_read_lock();
-        while (owner_running(lock, owner)) {
-                if (need_resched())
+        while (lock->owner == owner) {
+                /*
+                 * Ensure we emit the owner->on_cpu, dereference _after_
+                 * checking lock->owner still matches owner. If that fails,
+                 * owner might point to freed memory. If it still matches,
+                 * the rcu_read_lock() ensures the memory stays valid.
+                 */
+                barrier();
+
+                if (!owner->on_cpu || need_resched()) {
+                        ret = false;
                         break;
+                }
 
                 cpu_relax_lowlatency();
         }
         rcu_read_unlock();
 
-        /*
-         * We break out the loop above on need_resched() and when the
-         * owner changed, which is a sign for heavy contention. Return
-         * success only when lock->owner is NULL.
-         */
-        return lock->owner == NULL;
+        return ret;
 }
 
 /*
@@ -269,7 +260,7 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
                 return 0;
 
         rcu_read_lock();
-        owner = ACCESS_ONCE(lock->owner);
+        owner = READ_ONCE(lock->owner);
         if (owner)
                 retval = owner->on_cpu;
         rcu_read_unlock();
@@ -343,7 +334,7 @@ static bool mutex_optimistic_spin(struct mutex *lock,
                          * As such, when deadlock detection needs to be
                          * performed the optimistic spinning cannot be done.
                          */
-                        if (ACCESS_ONCE(ww->ctx))
+                        if (READ_ONCE(ww->ctx))
                                 break;
                 }
 
@@ -351,7 +342,7 @@ static bool mutex_optimistic_spin(struct mutex *lock,
                  * If there's an owner, wait for it to either
                  * release the lock or go to sleep.
                  */
-                owner = ACCESS_ONCE(lock->owner);
+                owner = READ_ONCE(lock->owner);
                 if (owner && !mutex_spin_on_owner(lock, owner))
                         break;
 
@@ -490,7 +481,7 @@ static inline int __sched
 __ww_mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
 {
         struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
-        struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
+        struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
 
         if (!hold_ctx)
                 return 0;