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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>
This commit is contained in:
Thomas Gleixner
Linus Torvalds
parent
0746aec3c7
commit
36cf3b5c3b
4 changed files with 74 additions and 85 deletions
138
kernel/futex.c
138
kernel/futex.c
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@ -120,6 +120,24 @@ static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS];
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/* Futex-fs vfsmount entry: */
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static struct vfsmount *futex_mnt;
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/*
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* Take mm->mmap_sem, when futex is shared
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*/
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static inline void futex_lock_mm(struct rw_semaphore *fshared)
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{
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if (fshared)
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down_read(fshared);
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}
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/*
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* Release mm->mmap_sem, when the futex is shared
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*/
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static inline void futex_unlock_mm(struct rw_semaphore *fshared)
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{
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if (fshared)
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up_read(fshared);
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}
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/*
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* We hash on the keys returned from get_futex_key (see below).
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*/
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@ -287,7 +305,18 @@ void drop_futex_key_refs(union futex_key *key)
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}
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EXPORT_SYMBOL_GPL(drop_futex_key_refs);
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static inline int get_futex_value_locked(u32 *dest, u32 __user *from)
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static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval)
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{
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u32 curval;
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pagefault_disable();
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curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
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pagefault_enable();
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return curval;
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}
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static int get_futex_value_locked(u32 *dest, u32 __user *from)
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{
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int ret;
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@ -620,9 +649,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
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newval = FUTEX_WAITERS | new_owner->pid;
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pagefault_disable();
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curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
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pagefault_enable();
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curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
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if (curval == -EFAULT)
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ret = -EFAULT;
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@ -659,9 +686,7 @@ static int unlock_futex_pi(u32 __user *uaddr, u32 uval)
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* There is no waiter, so we unlock the futex. The owner died
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* bit has not to be preserved here. We are the owner:
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*/
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pagefault_disable();
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oldval = futex_atomic_cmpxchg_inatomic(uaddr, uval, 0);
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pagefault_enable();
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oldval = cmpxchg_futex_value_locked(uaddr, uval, 0);
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if (oldval == -EFAULT)
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return oldval;
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@ -700,8 +725,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
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union futex_key key;
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int ret;
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if (fshared)
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down_read(fshared);
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futex_lock_mm(fshared);
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ret = get_futex_key(uaddr, fshared, &key);
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if (unlikely(ret != 0))
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@ -725,8 +749,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
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spin_unlock(&hb->lock);
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out:
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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return ret;
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}
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@ -746,8 +769,7 @@ futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared,
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int ret, op_ret, attempt = 0;
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retryfull:
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if (fshared)
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down_read(fshared);
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futex_lock_mm(fshared);
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ret = get_futex_key(uaddr1, fshared, &key1);
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if (unlikely(ret != 0))
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@ -793,7 +815,7 @@ retry:
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*/
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if (attempt++) {
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ret = futex_handle_fault((unsigned long)uaddr2,
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fshared, attempt);
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fshared, attempt);
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if (ret)
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goto out;
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goto retry;
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@ -803,8 +825,7 @@ retry:
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* If we would have faulted, release mmap_sem,
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* fault it in and start all over again.
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*/
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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ret = get_user(dummy, uaddr2);
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if (ret)
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@ -841,8 +862,8 @@ retry:
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if (hb1 != hb2)
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spin_unlock(&hb2->lock);
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out:
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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return ret;
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}
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@ -861,8 +882,7 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared,
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int ret, drop_count = 0;
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retry:
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if (fshared)
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down_read(fshared);
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futex_lock_mm(fshared);
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ret = get_futex_key(uaddr1, fshared, &key1);
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if (unlikely(ret != 0))
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@ -890,8 +910,7 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared,
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* If we would have faulted, release mmap_sem, fault
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* it in and start all over again.
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*/
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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ret = get_user(curval, uaddr1);
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@ -944,8 +963,7 @@ out_unlock:
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drop_futex_key_refs(&key1);
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out:
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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return ret;
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}
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@ -1113,10 +1131,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
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while (!ret) {
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newval = (uval & FUTEX_OWNER_DIED) | newtid;
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pagefault_disable();
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curval = futex_atomic_cmpxchg_inatomic(uaddr,
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uval, newval);
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pagefault_enable();
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curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
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if (curval == -EFAULT)
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ret = -EFAULT;
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@ -1134,6 +1149,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
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#define ARG3_SHARED 1
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static long futex_wait_restart(struct restart_block *restart);
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static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
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u32 val, ktime_t *abs_time)
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{
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@ -1148,8 +1164,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
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q.pi_state = NULL;
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retry:
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if (fshared)
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down_read(fshared);
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futex_lock_mm(fshared);
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ret = get_futex_key(uaddr, fshared, &q.key);
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if (unlikely(ret != 0))
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@ -1186,8 +1201,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
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* If we would have faulted, release mmap_sem, fault it in and
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* start all over again.
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*/
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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ret = get_user(uval, uaddr);
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@ -1206,8 +1220,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
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* Now the futex is queued and we have checked the data, we
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* don't want to hold mmap_sem while we sleep.
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*/
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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/*
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* There might have been scheduling since the queue_me(), as we
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@ -1285,8 +1298,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
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queue_unlock(&q, hb);
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out_release_sem:
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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return ret;
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}
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@ -1333,8 +1345,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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q.pi_state = NULL;
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retry:
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if (fshared)
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down_read(fshared);
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futex_lock_mm(fshared);
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ret = get_futex_key(uaddr, fshared, &q.key);
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if (unlikely(ret != 0))
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@ -1353,9 +1364,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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*/
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newval = current->pid;
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pagefault_disable();
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curval = futex_atomic_cmpxchg_inatomic(uaddr, 0, newval);
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pagefault_enable();
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curval = cmpxchg_futex_value_locked(uaddr, 0, newval);
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if (unlikely(curval == -EFAULT))
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goto uaddr_faulted;
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@ -1398,9 +1407,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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lock_taken = 1;
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}
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pagefault_disable();
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curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
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pagefault_enable();
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curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
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if (unlikely(curval == -EFAULT))
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goto uaddr_faulted;
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@ -1428,8 +1435,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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* exit to complete.
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*/
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queue_unlock(&q, hb);
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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cond_resched();
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goto retry;
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@ -1465,8 +1471,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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* Now the futex is queued and we have checked the data, we
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* don't want to hold mmap_sem while we sleep.
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*/
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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WARN_ON(!q.pi_state);
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/*
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@ -1480,8 +1485,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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ret = ret ? 0 : -EWOULDBLOCK;
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}
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if (fshared)
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down_read(fshared);
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futex_lock_mm(fshared);
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spin_lock(q.lock_ptr);
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if (!ret) {
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@ -1518,8 +1522,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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/* Unqueue and drop the lock */
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unqueue_me_pi(&q);
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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return ret != -EINTR ? ret : -ERESTARTNOINTR;
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@ -1527,8 +1530,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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queue_unlock(&q, hb);
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out_release_sem:
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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return ret;
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uaddr_faulted:
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@ -1550,8 +1552,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
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goto retry_unlocked;
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}
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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ret = get_user(uval, uaddr);
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if (!ret && (uval != -EFAULT))
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@ -1585,8 +1586,7 @@ retry:
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/*
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* First take all the futex related locks:
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*/
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if (fshared)
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down_read(fshared);
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futex_lock_mm(fshared);
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ret = get_futex_key(uaddr, fshared, &key);
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if (unlikely(ret != 0))
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@ -1601,11 +1601,9 @@ retry_unlocked:
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* again. If it succeeds then we can return without waking
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* anyone else up:
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*/
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if (!(uval & FUTEX_OWNER_DIED)) {
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pagefault_disable();
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uval = futex_atomic_cmpxchg_inatomic(uaddr, current->pid, 0);
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pagefault_enable();
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}
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if (!(uval & FUTEX_OWNER_DIED))
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uval = cmpxchg_futex_value_locked(uaddr, current->pid, 0);
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if (unlikely(uval == -EFAULT))
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goto pi_faulted;
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@ -1647,8 +1645,7 @@ retry_unlocked:
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out_unlock:
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spin_unlock(&hb->lock);
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out:
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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return ret;
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@ -1671,8 +1668,7 @@ pi_faulted:
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goto retry_unlocked;
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}
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if (fshared)
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up_read(fshared);
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futex_unlock_mm(fshared);
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ret = get_user(uval, uaddr);
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if (!ret && (uval != -EFAULT))
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@ -1729,8 +1725,8 @@ static int futex_fd(u32 __user *uaddr, int signal)
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if (printk_timed_ratelimit(&printk_interval, 60 * 60 * 1000)) {
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printk(KERN_WARNING "Process `%s' used FUTEX_FD, which "
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"will be removed from the kernel in June 2007\n",
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current->comm);
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"will be removed from the kernel in June 2007\n",
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current->comm);
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}
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ret = -EINVAL;
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@ -1908,10 +1904,8 @@ retry:
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* Wake robust non-PI futexes here. The wakeup of
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* PI futexes happens in exit_pi_state():
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*/
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if (!pi) {
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if (uval & FUTEX_WAITERS)
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if (!pi && (uval & FUTEX_WAITERS))
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futex_wake(uaddr, &curr->mm->mmap_sem, 1);
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}
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}
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return 0;
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}
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@ -29,12 +29,6 @@
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#include "rtmutex_common.h"
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#ifdef CONFIG_DEBUG_RT_MUTEXES
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# include "rtmutex-debug.h"
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#else
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# include "rtmutex.h"
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#endif
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# define TRACE_WARN_ON(x) WARN_ON(x)
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# define TRACE_BUG_ON(x) BUG_ON(x)
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@ -17,12 +17,6 @@
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#include "rtmutex_common.h"
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#ifdef CONFIG_DEBUG_RT_MUTEXES
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# include "rtmutex-debug.h"
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#else
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# include "rtmutex.h"
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#endif
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/*
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* lock->owner state tracking:
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*
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@ -103,7 +103,7 @@ static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
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static inline struct task_struct *rt_mutex_real_owner(struct rt_mutex *lock)
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{
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return (struct task_struct *)
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return (struct task_struct *)
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((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
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}
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@ -120,4 +120,11 @@ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
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struct task_struct *proxy_owner);
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extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
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struct task_struct *proxy_owner);
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#ifdef CONFIG_DEBUG_RT_MUTEXES
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# include "rtmutex-debug.h"
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#else
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# include "rtmutex.h"
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#endif
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#endif
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