This commit was manufactured by cvs2svn to create tag

[linux-2.6.git] / kernel / futex.c

diff --git a/kernel/futex.c b/kernel/futex.c
index 645a430..52bd8af 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -6,7 +6,7 @@
  *  (C) Copyright 2003 Red Hat Inc, All Rights Reserved
  *
  *  Removed page pinning, fix privately mapped COW pages and other cleanups
- *  (C) Copyright 2003, 2004 Jamie Lokier
+ *  (C) Copyright 2003 Jamie Lokier
  *
  *  Thanks to Ben LaHaise for yelling "hashed waitqueues" loudly
  *  enough at me, Linus for the original (flawed) idea, Matthew
@@ -489,24 +489,9 @@ static int futex_wait(unsigned long uaddr, int val, unsigned long time)
        queue_me(&q, -1, NULL);
 
        /*
-        * Access the page AFTER the futex is queued.
-        * Order is important:
-        *
-        *   Userspace waiter: val = var; if (cond(val)) futex_wait(&var, val);
-        *   Userspace waker:  if (cond(var)) { var = new; futex_wake(&var); }
-        *
-        * The basic logical guarantee of a futex is that it blocks ONLY
-        * if cond(var) is known to be true at the time of blocking, for
-        * any cond.  If we queued after testing *uaddr, that would open
-        * a race condition where we could block indefinitely with
-        * cond(var) false, which would violate the guarantee.
-        *
-        * A consequence is that futex_wait() can return zero and absorb
-        * a wakeup when *uaddr != val on entry to the syscall.  This is
-        * rare, but normal.
-        *
+        * Access the page after the futex is queued.
         * We hold the mmap semaphore, so the mapping cannot have changed
-        * since we looked it up in get_futex_key.
+        * since we looked it up.
         */
        if (get_user(curval, (int __user *)uaddr) != 0) {
                ret = -EFAULT;
@@ -747,7 +732,7 @@ static int __init init(void)
 
        for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
                INIT_LIST_HEAD(&futex_queues[i].chain);
-               spin_lock_init(&futex_queues[i].lock);
+               futex_queues[i].lock = SPIN_LOCK_UNLOCKED;
        }
        return 0;
 }