FUTEX: Tidy up the code

The recent PRIVATE and REQUEUE_PI changes to the futex code made it hard to
read.  Tidy it up.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/futex.c b/kernel/futex.c
index 45490be..5c3f45d 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -121,6 +121,24 @@ static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS];
 static struct vfsmount *futex_mnt;
 
 /*
+ * Take mm->mmap_sem, when futex is shared
+ */
+static inline void futex_lock_mm(struct rw_semaphore *fshared)
+{
+       if (fshared)
+               down_read(fshared);
+}
+
+/*
+ * Release mm->mmap_sem, when the futex is shared
+ */
+static inline void futex_unlock_mm(struct rw_semaphore *fshared)
+{
+       if (fshared)
+               up_read(fshared);
+}
+
+/*
  * We hash on the keys returned from get_futex_key (see below).
  */
 static struct futex_hash_bucket *hash_futex(union futex_key *key)
@@ -287,7 +305,18 @@ void drop_futex_key_refs(union futex_key *key)
 }
 EXPORT_SYMBOL_GPL(drop_futex_key_refs);
 
-static inline int get_futex_value_locked(u32 *dest, u32 __user *from)
+static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval)
+{
+       u32 curval;
+
+       pagefault_disable();
+       curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
+       pagefault_enable();
+
+       return curval;
+}
+
+static int get_futex_value_locked(u32 *dest, u32 __user *from)
 {
        int ret;
 
@@ -620,9 +649,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
 
                newval = FUTEX_WAITERS | new_owner->pid;
 
-               pagefault_disable();
-               curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
-               pagefault_enable();
+               curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
 
                if (curval == -EFAULT)
                        ret = -EFAULT;
@@ -659,9 +686,7 @@ static int unlock_futex_pi(u32 __user *uaddr, u32 uval)
         * There is no waiter, so we unlock the futex. The owner died
         * bit has not to be preserved here. We are the owner:
         */
-       pagefault_disable();
-       oldval = futex_atomic_cmpxchg_inatomic(uaddr, uval, 0);
-       pagefault_enable();
+       oldval = cmpxchg_futex_value_locked(uaddr, uval, 0);
 
        if (oldval == -EFAULT)
                return oldval;
@@ -700,8 +725,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
        union futex_key key;
        int ret;
 
-       if (fshared)
-               down_read(fshared);
+       futex_lock_mm(fshared);
 
        ret = get_futex_key(uaddr, fshared, &key);
        if (unlikely(ret != 0))
@@ -725,8 +749,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
 
        spin_unlock(&hb->lock);
 out:
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
        return ret;
 }
 
@@ -746,8 +769,7 @@ futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared,
        int ret, op_ret, attempt = 0;
 
 retryfull:
-       if (fshared)
-               down_read(fshared);
+       futex_lock_mm(fshared);
 
        ret = get_futex_key(uaddr1, fshared, &key1);
        if (unlikely(ret != 0))
@@ -793,7 +815,7 @@ retry:
                 */
                if (attempt++) {
                        ret = futex_handle_fault((unsigned long)uaddr2,
-                                               fshared, attempt);
+                                                fshared, attempt);
                        if (ret)
                                goto out;
                        goto retry;
@@ -803,8 +825,7 @@ retry:
                 * If we would have faulted, release mmap_sem,
                 * fault it in and start all over again.
                 */
-               if (fshared)
-                       up_read(fshared);
+               futex_unlock_mm(fshared);
 
                ret = get_user(dummy, uaddr2);
                if (ret)
@@ -841,8 +862,8 @@ retry:
        if (hb1 != hb2)
                spin_unlock(&hb2->lock);
 out:
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
+
        return ret;
 }
 
@@ -861,8 +882,7 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared,
        int ret, drop_count = 0;
 
  retry:
-       if (fshared)
-               down_read(fshared);
+       futex_lock_mm(fshared);
 
        ret = get_futex_key(uaddr1, fshared, &key1);
        if (unlikely(ret != 0))
@@ -890,8 +910,7 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared,
                         * If we would have faulted, release mmap_sem, fault
                         * it in and start all over again.
                         */
-                       if (fshared)
-                               up_read(fshared);
+                       futex_unlock_mm(fshared);
 
                        ret = get_user(curval, uaddr1);
 
@@ -944,8 +963,7 @@ out_unlock:
                drop_futex_key_refs(&key1);
 
 out:
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
        return ret;
 }
 
@@ -1113,10 +1131,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
        while (!ret) {
                newval = (uval & FUTEX_OWNER_DIED) | newtid;
 
-               pagefault_disable();
-               curval = futex_atomic_cmpxchg_inatomic(uaddr,
-                                                      uval, newval);
-               pagefault_enable();
+               curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
 
                if (curval == -EFAULT)
                        ret = -EFAULT;
@@ -1134,6 +1149,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
 #define ARG3_SHARED  1
 
 static long futex_wait_restart(struct restart_block *restart);
+
 static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
                      u32 val, ktime_t *abs_time)
 {
@@ -1148,8 +1164,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
 
        q.pi_state = NULL;
  retry:
-       if (fshared)
-               down_read(fshared);
+       futex_lock_mm(fshared);
 
        ret = get_futex_key(uaddr, fshared, &q.key);
        if (unlikely(ret != 0))
@@ -1186,8 +1201,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
                 * If we would have faulted, release mmap_sem, fault it in and
                 * start all over again.
                 */
-               if (fshared)
-                       up_read(fshared);
+               futex_unlock_mm(fshared);
 
                ret = get_user(uval, uaddr);
 
@@ -1206,8 +1220,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
         * Now the futex is queued and we have checked the data, we
         * don't want to hold mmap_sem while we sleep.
         */
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
 
        /*
         * There might have been scheduling since the queue_me(), as we
@@ -1285,8 +1298,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
        queue_unlock(&q, hb);
 
  out_release_sem:
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
        return ret;
 }
 
@@ -1333,8 +1345,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
 
        q.pi_state = NULL;
  retry:
-       if (fshared)
-               down_read(fshared);
+       futex_lock_mm(fshared);
 
        ret = get_futex_key(uaddr, fshared, &q.key);
        if (unlikely(ret != 0))
@@ -1353,9 +1364,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
         */
        newval = current->pid;
 
-       pagefault_disable();
-       curval = futex_atomic_cmpxchg_inatomic(uaddr, 0, newval);
-       pagefault_enable();
+       curval = cmpxchg_futex_value_locked(uaddr, 0, newval);
 
        if (unlikely(curval == -EFAULT))
                goto uaddr_faulted;
@@ -1398,9 +1407,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
                lock_taken = 1;
        }
 
-       pagefault_disable();
-       curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
-       pagefault_enable();
+       curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
 
        if (unlikely(curval == -EFAULT))
                goto uaddr_faulted;
@@ -1428,8 +1435,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
                         * exit to complete.
                         */
                        queue_unlock(&q, hb);
-                       if (fshared)
-                               up_read(fshared);
+                       futex_unlock_mm(fshared);
                        cond_resched();
                        goto retry;
 
@@ -1465,8 +1471,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
         * Now the futex is queued and we have checked the data, we
         * don't want to hold mmap_sem while we sleep.
         */
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
 
        WARN_ON(!q.pi_state);
        /*
@@ -1480,8 +1485,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
                ret = ret ? 0 : -EWOULDBLOCK;
        }
 
-       if (fshared)
-               down_read(fshared);
+       futex_lock_mm(fshared);
        spin_lock(q.lock_ptr);
 
        if (!ret) {
@@ -1518,8 +1522,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
 
        /* Unqueue and drop the lock */
        unqueue_me_pi(&q);
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
 
        return ret != -EINTR ? ret : -ERESTARTNOINTR;
 
@@ -1527,8 +1530,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
        queue_unlock(&q, hb);
 
  out_release_sem:
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
        return ret;
 
  uaddr_faulted:
@@ -1550,8 +1552,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
                goto retry_unlocked;
        }
 
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
 
        ret = get_user(uval, uaddr);
        if (!ret && (uval != -EFAULT))
@@ -1585,8 +1586,7 @@ retry:
        /*
         * First take all the futex related locks:
         */
-       if (fshared)
-               down_read(fshared);
+       futex_lock_mm(fshared);
 
        ret = get_futex_key(uaddr, fshared, &key);
        if (unlikely(ret != 0))
@@ -1601,11 +1601,9 @@ retry_unlocked:
         * again. If it succeeds then we can return without waking
         * anyone else up:
         */
-       if (!(uval & FUTEX_OWNER_DIED)) {
-               pagefault_disable();
-               uval = futex_atomic_cmpxchg_inatomic(uaddr, current->pid, 0);
-               pagefault_enable();
-       }
+       if (!(uval & FUTEX_OWNER_DIED))
+               uval = cmpxchg_futex_value_locked(uaddr, current->pid, 0);
+
 
        if (unlikely(uval == -EFAULT))
                goto pi_faulted;
@@ -1647,8 +1645,7 @@ retry_unlocked:
 out_unlock:
        spin_unlock(&hb->lock);
 out:
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
 
        return ret;
 
@@ -1671,8 +1668,7 @@ pi_faulted:
                goto retry_unlocked;
        }
 
-       if (fshared)
-               up_read(fshared);
+       futex_unlock_mm(fshared);
 
        ret = get_user(uval, uaddr);
        if (!ret && (uval != -EFAULT))
@@ -1729,8 +1725,8 @@ static int futex_fd(u32 __user *uaddr, int signal)
 
        if (printk_timed_ratelimit(&printk_interval, 60 * 60 * 1000)) {
                printk(KERN_WARNING "Process `%s' used FUTEX_FD, which "
-                       "will be removed from the kernel in June 2007\n",
-                       current->comm);
+                      "will be removed from the kernel in June 2007\n",
+                      current->comm);
        }
 
        ret = -EINVAL;
@@ -1908,10 +1904,8 @@ retry:
                 * Wake robust non-PI futexes here. The wakeup of
                 * PI futexes happens in exit_pi_state():
                 */
-               if (!pi) {
-                       if (uval & FUTEX_WAITERS)
+               if (!pi && (uval & FUTEX_WAITERS))
                                futex_wake(uaddr, &curr->mm->mmap_sem, 1);
-               }
        }
        return 0;
 }

diff --git a/kernel/rtmutex-debug.c b/kernel/rtmutex-debug.c
index da8d6bf..5aedbee 100644 (file)
--- a/kernel/rtmutex-debug.c
+++ b/kernel/rtmutex-debug.c
@@ -29,12 +29,6 @@
 
 #include "rtmutex_common.h"
 
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-# include "rtmutex-debug.h"
-#else
-# include "rtmutex.h"
-#endif
-
 # define TRACE_WARN_ON(x)                      WARN_ON(x)
 # define TRACE_BUG_ON(x)                       BUG_ON(x)
 

diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 17d28ce..8cd9bd2 100644 (file)
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -17,12 +17,6 @@
 
 #include "rtmutex_common.h"
 
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-# include "rtmutex-debug.h"
-#else
-# include "rtmutex.h"
-#endif
-
 /*
  * lock->owner state tracking:
  *

diff --git a/kernel/rtmutex_common.h b/kernel/rtmutex_common.h
index 9c75856..2d3b835 100644 (file)
--- a/kernel/rtmutex_common.h
+++ b/kernel/rtmutex_common.h
@@ -103,7 +103,7 @@ static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
 
 static inline struct task_struct *rt_mutex_real_owner(struct rt_mutex *lock)
 {
-       return (struct task_struct *)
+       return (struct task_struct *)
                ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
 }
 
@@ -120,4 +120,11 @@ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
                                       struct task_struct *proxy_owner);
 extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
                                  struct task_struct *proxy_owner);
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+# include "rtmutex-debug.h"
+#else
+# include "rtmutex.h"
+#endif
+
 #endif