X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=kernel%2Ffutex.c;h=db9824de8bf061323b734d88377a6fa606fb9a86;hb=366ca51f30de1cbb5b356c70b7bb22051c558e41;hp=32710451dc20ea7763cc22d02f0363c9155a772f;hpb=0b776eb5426752d4e53354ac89e3710d857e09a7;p=linux-2.6-omap-h63xx.git diff --git a/kernel/futex.c b/kernel/futex.c index 32710451dc2..db9824de8bf 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -181,8 +181,8 @@ static inline int match_futex(union futex_key *key1, union futex_key *key2) * For other futexes, it points to ¤t->mm->mmap_sem and * caller must have taken the reader lock. but NOT any spinlocks. */ -int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, - union futex_key *key) +static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, + union futex_key *key) { unsigned long address = (unsigned long)uaddr; struct mm_struct *mm = current->mm; @@ -268,14 +268,13 @@ int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, } return err; } -EXPORT_SYMBOL_GPL(get_futex_key); /* * Take a reference to the resource addressed by a key. * Can be called while holding spinlocks. * */ -inline void get_futex_key_refs(union futex_key *key) +static void get_futex_key_refs(union futex_key *key) { if (key->both.ptr == 0) return; @@ -288,13 +287,12 @@ inline void get_futex_key_refs(union futex_key *key) break; } } -EXPORT_SYMBOL_GPL(get_futex_key_refs); /* * Drop a reference to the resource addressed by a key. * The hash bucket spinlock must not be held. */ -void drop_futex_key_refs(union futex_key *key) +static void drop_futex_key_refs(union futex_key *key) { if (!key->both.ptr) return; @@ -307,7 +305,6 @@ void drop_futex_key_refs(union futex_key *key) break; } } -EXPORT_SYMBOL_GPL(drop_futex_key_refs); static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval) { @@ -661,7 +658,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this) if (curval == -EFAULT) ret = -EFAULT; - if (curval != uval) + else if (curval != uval) ret = -EINVAL; if (ret) { spin_unlock(&pi_state->pi_mutex.wait_lock); @@ -1100,15 +1097,15 @@ static void unqueue_me_pi(struct futex_q *q) } /* - * Fixup the pi_state owner with current. + * Fixup the pi_state owner with the new owner. * * Must be called with hash bucket lock held and mm->sem held for non * private futexes. */ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, - struct task_struct *curr) + struct task_struct *newowner) { - u32 newtid = task_pid_vnr(curr) | FUTEX_WAITERS; + u32 newtid = task_pid_vnr(newowner) | FUTEX_WAITERS; struct futex_pi_state *pi_state = q->pi_state; u32 uval, curval, newval; int ret; @@ -1122,12 +1119,12 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, } else newtid |= FUTEX_OWNER_DIED; - pi_state->owner = curr; + pi_state->owner = newowner; - spin_lock_irq(&curr->pi_lock); + spin_lock_irq(&newowner->pi_lock); WARN_ON(!list_empty(&pi_state->list)); - list_add(&pi_state->list, &curr->pi_state_list); - spin_unlock_irq(&curr->pi_lock); + list_add(&pi_state->list, &newowner->pi_state_list); + spin_unlock_irq(&newowner->pi_lock); /* * We own it, so we have to replace the pending owner @@ -1152,9 +1149,9 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, /* * In case we must use restart_block to restart a futex_wait, - * we encode in the 'arg3' shared capability + * we encode in the 'flags' shared capability */ -#define ARG3_SHARED 1 +#define FLAGS_SHARED 1 static long futex_wait_restart(struct restart_block *restart); @@ -1293,12 +1290,13 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, struct restart_block *restart; restart = ¤t_thread_info()->restart_block; restart->fn = futex_wait_restart; - restart->arg0 = (unsigned long)uaddr; - restart->arg1 = (unsigned long)val; - restart->arg2 = (unsigned long)abs_time; - restart->arg3 = 0; + restart->futex.uaddr = (u32 *)uaddr; + restart->futex.val = val; + restart->futex.time = abs_time->tv64; + restart->futex.flags = 0; + if (fshared) - restart->arg3 |= ARG3_SHARED; + restart->futex.flags |= FLAGS_SHARED; return -ERESTART_RESTARTBLOCK; } @@ -1313,15 +1311,15 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, static long futex_wait_restart(struct restart_block *restart) { - u32 __user *uaddr = (u32 __user *)restart->arg0; - u32 val = (u32)restart->arg1; - ktime_t *abs_time = (ktime_t *)restart->arg2; + u32 __user *uaddr = (u32 __user *)restart->futex.uaddr; struct rw_semaphore *fshared = NULL; + ktime_t t; + t.tv64 = restart->futex.time; restart->fn = do_no_restart_syscall; - if (restart->arg3 & ARG3_SHARED) + if (restart->futex.flags & FLAGS_SHARED) fshared = ¤t->mm->mmap_sem; - return (long)futex_wait(uaddr, fshared, val, abs_time); + return (long)futex_wait(uaddr, fshared, restart->futex.val, &t); } @@ -1510,9 +1508,40 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, * when we were on the way back before we locked the * hash bucket. */ - if (q.pi_state->owner == curr && - rt_mutex_trylock(&q.pi_state->pi_mutex)) { - ret = 0; + if (q.pi_state->owner == curr) { + /* + * Try to get the rt_mutex now. This might + * fail as some other task acquired the + * rt_mutex after we removed ourself from the + * rt_mutex waiters list. + */ + if (rt_mutex_trylock(&q.pi_state->pi_mutex)) + ret = 0; + else { + /* + * pi_state is incorrect, some other + * task did a lock steal and we + * returned due to timeout or signal + * without taking the rt_mutex. Too + * late. We can access the + * rt_mutex_owner without locking, as + * the other task is now blocked on + * the hash bucket lock. Fix the state + * up. + */ + struct task_struct *owner; + int res; + + owner = rt_mutex_owner(&q.pi_state->pi_mutex); + res = fixup_pi_state_owner(uaddr, &q, owner); + + WARN_ON(rt_mutex_owner(&q.pi_state->pi_mutex) != + owner); + + /* propagate -EFAULT, if the fixup failed */ + if (res) + ret = res; + } } else { /* * Paranoia check. If we did not take the lock