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author | Thomas Gleixner <tglx@linutronix.de> | 2007-07-15 23:41:20 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-16 09:05:49 -0700 |
commit | 36cf3b5c3b7228bcf5124c530d50080b61a59f69 (patch) | |
tree | c131870530e22371da47ad7b717f61d7cb00a84e /kernel/futex.c | |
parent | 0746aec3c75f23de0148774ac50cf73161f09d68 (diff) | |
download | kernel_samsung_smdk4412-36cf3b5c3b7228bcf5124c530d50080b61a59f69.zip kernel_samsung_smdk4412-36cf3b5c3b7228bcf5124c530d50080b61a59f69.tar.gz kernel_samsung_smdk4412-36cf3b5c3b7228bcf5124c530d50080b61a59f69.tar.bz2 |
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>
Diffstat (limited to 'kernel/futex.c')
-rw-r--r-- | kernel/futex.c | 138 |
1 files changed, 66 insertions, 72 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 45490be..5c3f45d 100644 --- 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; } |