diff options
| -rw-r--r-- | include/linux/futex.h | 9 | ||||
| -rw-r--r-- | kernel/futex.c | 415 | ||||
| -rw-r--r-- | kernel/futex_compat.c | 3 | ||||
| -rw-r--r-- | kernel/rtmutex.c | 41 | ||||
| -rw-r--r-- | kernel/rtmutex_common.h | 34 |
5 files changed, 43 insertions, 459 deletions
diff --git a/include/linux/futex.h b/include/linux/futex.h index 899fc7f20ed..99650353adf 100644 --- a/include/linux/futex.h +++ b/include/linux/futex.h @@ -17,7 +17,6 @@ union ktime; #define FUTEX_LOCK_PI 6 #define FUTEX_UNLOCK_PI 7 #define FUTEX_TRYLOCK_PI 8 -#define FUTEX_CMP_REQUEUE_PI 9 #define FUTEX_PRIVATE_FLAG 128 #define FUTEX_CMD_MASK ~FUTEX_PRIVATE_FLAG @@ -98,14 +97,9 @@ struct robust_list_head { #define FUTEX_OWNER_DIED 0x40000000 /* - * Some processes have been requeued on this PI-futex - */ -#define FUTEX_WAITER_REQUEUED 0x20000000 - -/* * The rest of the robust-futex field is for the TID: */ -#define FUTEX_TID_MASK 0x0fffffff +#define FUTEX_TID_MASK 0x3fffffff /* * This limit protects against a deliberately circular list. @@ -139,7 +133,6 @@ handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi); #define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */ union futex_key { - u32 __user *uaddr; struct { unsigned long pgoff; struct inode *inode; diff --git a/kernel/futex.c b/kernel/futex.c index 3b7f7713d9a..df248f5e083 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -56,12 +56,6 @@ #include "rtmutex_common.h" -#ifdef CONFIG_DEBUG_RT_MUTEXES -# include "rtmutex-debug.h" -#else -# include "rtmutex.h" -#endif - #define FUTEX_HASHBITS (CONFIG_BASE_SMALL ? 4 : 8) /* @@ -111,12 +105,6 @@ struct futex_q { /* Optional priority inheritance state: */ struct futex_pi_state *pi_state; struct task_struct *task; - - /* - * This waiter is used in case of requeue from a - * normal futex to a PI-futex - */ - struct rt_mutex_waiter waiter; }; /* @@ -216,9 +204,6 @@ int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared, if (unlikely((vma->vm_flags & (VM_IO|VM_READ)) != VM_READ)) return (vma->vm_flags & VM_IO) ? -EPERM : -EACCES; - /* Save the user address in the ley */ - key->uaddr = uaddr; - /* * Private mappings are handled in a simple way. * @@ -636,8 +621,6 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this) int ret = 0; newval = FUTEX_WAITERS | new_owner->pid; - /* Keep the FUTEX_WAITER_REQUEUED flag if it was set */ - newval |= (uval & FUTEX_WAITER_REQUEUED); pagefault_disable(); curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval); @@ -750,259 +733,6 @@ out: } /* - * Called from futex_requeue_pi. - * Set FUTEX_WAITERS and FUTEX_WAITER_REQUEUED flags on the - * PI-futex value; search its associated pi_state if an owner exist - * or create a new one without owner. - */ -static inline int -lookup_pi_state_for_requeue(u32 __user *uaddr, struct futex_hash_bucket *hb, - union futex_key *key, - struct futex_pi_state **pi_state) -{ - u32 curval, uval, newval; - -retry: - /* - * We can't handle a fault cleanly because we can't - * release the locks here. Simply return the fault. - */ - if (get_futex_value_locked(&curval, uaddr)) - return -EFAULT; - - /* set the flags FUTEX_WAITERS and FUTEX_WAITER_REQUEUED */ - if ((curval & (FUTEX_WAITERS | FUTEX_WAITER_REQUEUED)) - != (FUTEX_WAITERS | FUTEX_WAITER_REQUEUED)) { - /* - * No waiters yet, we prepare the futex to have some waiters. - */ - - uval = curval; - newval = uval | FUTEX_WAITERS | FUTEX_WAITER_REQUEUED; - - pagefault_disable(); - curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval); - pagefault_enable(); - - if (unlikely(curval == -EFAULT)) - return -EFAULT; - if (unlikely(curval != uval)) - goto retry; - } - - if (!(curval & FUTEX_TID_MASK) - || lookup_pi_state(curval, hb, key, pi_state)) { - /* the futex has no owner (yet) or the lookup failed: - allocate one pi_state without owner */ - - *pi_state = alloc_pi_state(); - - /* Already stores the key: */ - (*pi_state)->key = *key; - - /* init the mutex without owner */ - __rt_mutex_init(&(*pi_state)->pi_mutex, NULL); - } - - return 0; -} - -/* - * Keep the first nr_wake waiter from futex1, wake up one, - * and requeue the next nr_requeue waiters following hashed on - * one physical page to another physical page (PI-futex uaddr2) - */ -static int futex_requeue_pi(u32 __user *uaddr1, - struct rw_semaphore *fshared, - u32 __user *uaddr2, - int nr_wake, int nr_requeue, u32 *cmpval) -{ - union futex_key key1, key2; - struct futex_hash_bucket *hb1, *hb2; - struct plist_head *head1; - struct futex_q *this, *next; - struct futex_pi_state *pi_state2 = NULL; - struct rt_mutex_waiter *waiter, *top_waiter = NULL; - struct rt_mutex *lock2 = NULL; - int ret, drop_count = 0; - - if (refill_pi_state_cache()) - return -ENOMEM; - -retry: - /* - * First take all the futex related locks: - */ - if (fshared) - down_read(fshared); - - ret = get_futex_key(uaddr1, fshared, &key1); - if (unlikely(ret != 0)) - goto out; - ret = get_futex_key(uaddr2, fshared, &key2); - if (unlikely(ret != 0)) - goto out; - - hb1 = hash_futex(&key1); - hb2 = hash_futex(&key2); - - double_lock_hb(hb1, hb2); - - if (likely(cmpval != NULL)) { - u32 curval; - - ret = get_futex_value_locked(&curval, uaddr1); - - if (unlikely(ret)) { - spin_unlock(&hb1->lock); - if (hb1 != hb2) - spin_unlock(&hb2->lock); - - /* - * If we would have faulted, release mmap_sem, fault - * it in and start all over again. - */ - if (fshared) - up_read(fshared); - - ret = get_user(curval, uaddr1); - - if (!ret) - goto retry; - - return ret; - } - if (curval != *cmpval) { - ret = -EAGAIN; - goto out_unlock; - } - } - - head1 = &hb1->chain; - plist_for_each_entry_safe(this, next, head1, list) { - if (!match_futex (&this->key, &key1)) - continue; - if (++ret <= nr_wake) { - wake_futex(this); - } else { - /* - * FIRST: get and set the pi_state - */ - if (!pi_state2) { - int s; - /* do this only the first time we requeue someone */ - s = lookup_pi_state_for_requeue(uaddr2, hb2, - &key2, &pi_state2); - if (s) { - ret = s; - goto out_unlock; - } - - lock2 = &pi_state2->pi_mutex; - spin_lock(&lock2->wait_lock); - - /* Save the top waiter of the wait_list */ - if (rt_mutex_has_waiters(lock2)) - top_waiter = rt_mutex_top_waiter(lock2); - } else - atomic_inc(&pi_state2->refcount); - - - this->pi_state = pi_state2; - - /* - * SECOND: requeue futex_q to the correct hashbucket - */ - - /* - * If key1 and key2 hash to the same bucket, no need to - * requeue. - */ - if (likely(head1 != &hb2->chain)) { - plist_del(&this->list, &hb1->chain); - plist_add(&this->list, &hb2->chain); - this->lock_ptr = &hb2->lock; -#ifdef CONFIG_DEBUG_PI_LIST - this->list.plist.lock = &hb2->lock; -#endif - } - this->key = key2; - get_futex_key_refs(&key2); - drop_count++; - - - /* - * THIRD: queue it to lock2 - */ - spin_lock_irq(&this->task->pi_lock); - waiter = &this->waiter; - waiter->task = this->task; - waiter->lock = lock2; - plist_node_init(&waiter->list_entry, this->task->prio); - plist_node_init(&waiter->pi_list_entry, this->task->prio); - plist_add(&waiter->list_entry, &lock2->wait_list); - this->task->pi_blocked_on = waiter; - spin_unlock_irq(&this->task->pi_lock); - - if (ret - nr_wake >= nr_requeue) - break; - } - } - - /* If we've requeued some tasks and the top_waiter of the rt_mutex - has changed, we must adjust the priority of the owner, if any */ - if (drop_count) { - struct task_struct *owner = rt_mutex_owner(lock2); - if (owner && - (top_waiter != (waiter = rt_mutex_top_waiter(lock2)))) { - int chain_walk = 0; - - spin_lock_irq(&owner->pi_lock); - if (top_waiter) - plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters); - else - /* - * There was no waiters before the requeue, - * the flag must be updated - */ - mark_rt_mutex_waiters(lock2); - - plist_add(&waiter->pi_list_entry, &owner->pi_waiters); - __rt_mutex_adjust_prio(owner); - if (owner->pi_blocked_on) { - chain_walk = 1; - get_task_struct(owner); - } - - spin_unlock_irq(&owner->pi_lock); - spin_unlock(&lock2->wait_lock); - - if (chain_walk) - rt_mutex_adjust_prio_chain(owner, 0, lock2, NULL, - current); - } else { - /* No owner or the top_waiter does not change */ - mark_rt_mutex_waiters(lock2); - spin_unlock(&lock2->wait_lock); - } - } - -out_unlock: - spin_unlock(&hb1->lock); - if (hb1 != hb2) - spin_unlock(&hb2->lock); - - /* drop_futex_key_refs() must be called outside the spinlocks. */ - while (--drop_count >= 0) - drop_futex_key_refs(&key1); - -out: - if (fshared) - up_read(fshared); - return ret; -} - -/* * Wake up all waiters hashed on the physical page that is mapped * to this virtual address: */ @@ -1384,7 +1114,6 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, while (!ret) { newval = (uval & FUTEX_OWNER_DIED) | newtid; - newval |= (uval & FUTEX_WAITER_REQUEUED); pagefault_disable(); curval = futex_atomic_cmpxchg_inatomic(uaddr, @@ -1416,7 +1145,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, struct futex_q q; u32 uval; int ret; - struct hrtimer_sleeper t, *to = NULL; + struct hrtimer_sleeper t; int rem = 0; q.pi_state = NULL; @@ -1472,14 +1201,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, if (uval != val) goto out_unlock_release_sem; - /* - * This rt_mutex_waiter structure is prepared here and will - * be used only if this task is requeued from a normal futex to - * a PI-futex with futex_requeue_pi. - */ - debug_rt_mutex_init_waiter(&q.waiter); - q.waiter.task = NULL; - /* Only actually queue if *uaddr contained val. */ __queue_me(&q, hb); @@ -1510,7 +1231,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, if (!abs_time) schedule(); else { - to = &t; hrtimer_init(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); hrtimer_init_sleeper(&t, current); t.timer.expires = *abs_time; @@ -1538,67 +1258,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared, * we are the only user of it. */ - if (q.pi_state) { - /* - * We were woken but have been requeued on a PI-futex. - * We have to complete the lock acquisition by taking - * the rtmutex. - */ - - struct rt_mutex *lock = &q.pi_state->pi_mutex; - - spin_lock(&lock->wait_lock); - if (unlikely(q.waiter.task)) { - remove_waiter(lock, &q.waiter); - } - spin_unlock(&lock->wait_lock); - - if (rem) - ret = -ETIMEDOUT; - else - ret = rt_mutex_timed_lock(lock, to, 1); - - if (fshared) - down_read(fshared); - spin_lock(q.lock_ptr); - - /* - * Got the lock. We might not be the anticipated owner if we - * did a lock-steal - fix up the PI-state in that case. - */ - if (!ret && q.pi_state->owner != curr) { - /* - * We MUST play with the futex we were requeued on, - * NOT the current futex. - * We can retrieve it from the key of the pi_state - */ - uaddr = q.pi_state->key.uaddr; - - ret = fixup_pi_state_owner(uaddr, &q, curr); - } else { - /* - * Catch the rare case, where the lock was released - * when we were on the way back before we locked - * the hash bucket. - */ - if (ret && q.pi_state->owner == curr) { - if (rt_mutex_trylock(&q.pi_state->pi_mutex)) - ret = 0; - } - } - - /* Unqueue and drop the lock */ - unqueue_me_pi(&q); - if (fshared) - up_read(fshared); - - debug_rt_mutex_free_waiter(&q.waiter); - - return ret; - } - - debug_rt_mutex_free_waiter(&q.waiter); - /* If we were woken (and unqueued), we succeeded, whatever. */ if (!unqueue_me(&q)) return 0; @@ -1648,51 +1307,6 @@ static long futex_wait_restart(struct restart_block *restart) } -static void set_pi_futex_owner(struct futex_hash_bucket *hb, - union futex_key *key, struct task_struct *p) -{ - struct plist_head *head; - struct futex_q *this, *next; - struct futex_pi_state *pi_state = NULL; - struct rt_mutex *lock; - - /* Search a waiter that should already exists */ - - head = &hb->chain; - - plist_for_each_entry_safe(this, next, head, list) { - if (match_futex (&this->key, key)) { - pi_state = this->pi_state; - break; - } - } - - BUG_ON(!pi_state); - - /* set p as pi_state's owner */ - lock = &pi_state->pi_mutex; - - spin_lock(&lock->wait_lock); - spin_lock_irq(&p->pi_lock); - - list_add(&pi_state->list, &p->pi_state_list); - pi_state->owner = p; - - - /* set p as pi_mutex's owner */ - debug_rt_mutex_proxy_lock(lock, p); - WARN_ON(rt_mutex_owner(lock)); - rt_mutex_set_owner(lock, p, 0); - rt_mutex_deadlock_account_lock(lock, p); - - plist_add(&rt_mutex_top_waiter(lock)->pi_list_entry, - &p->pi_waiters); - __rt_mutex_adjust_prio(p); - - spin_unlock_irq(&p->pi_lock); - spin_unlock(&lock->wait_lock); -} - /* * Userspace tried a 0 -> TID atomic transition of the futex value * and failed. The kernel side here does the whole locking operation: @@ -1753,8 +1367,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, * situation and we return success to user space. */ if (unlikely((curval & FUTEX_TID_MASK) == current->pid)) { - if (!(curval & FUTEX_WAITER_REQUEUED)) - ret = -EDEADLK; + ret = -EDEADLK; goto out_unlock_release_sem; } @@ -1774,14 +1387,14 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, /* * There are two cases, where a futex might have no owner (the - * owner TID is 0): OWNER_DIED or REQUEUE. We take over the - * futex in this case. We also do an unconditional take over, - * when the owner of the futex died. + * owner TID is 0): OWNER_DIED. We take over the futex in this + * case. We also do an unconditional take over, when the owner + * of the futex died. * * This is safe as we are protected by the hash bucket lock ! */ if (unlikely(ownerdied || !(curval & FUTEX_TID_MASK))) { - /* Keep the OWNER_DIED and REQUEUE bits */ + /* Keep the OWNER_DIED bit */ newval = (curval & ~FUTEX_TID_MASK) | current->pid; ownerdied = 0; lock_taken = 1; @@ -1797,14 +1410,10 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared, goto retry_locked; /* - * We took the lock due to requeue or owner died take over. + * We took the lock due to owner died take over. */ - if (unlikely(lock_taken)) { - /* For requeue we need to fixup the pi_futex */ - if (curval & FUTEX_WAITER_REQUEUED) - set_pi_futex_owner(hb, &q.key, curr); + if (unlikely(lock_taken)) goto out_unlock_release_sem; - } /* * We dont have the lock. Look up the PI state (or create it if @@ -2289,8 +1898,6 @@ retry: * userspace. */ mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; - /* Also keep the FUTEX_WAITER_REQUEUED flag if set */ - mval |= (uval & FUTEX_WAITER_REQUEUED); nval = futex_atomic_cmpxchg_inatomic(uaddr, uval, mval); if (nval == -EFAULT) @@ -2427,9 +2034,6 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, case FUTEX_TRYLOCK_PI: ret = futex_lock_pi(uaddr, fshared, 0, timeout, 1); break; - case FUTEX_CMP_REQUEUE_PI: - ret = futex_requeue_pi(uaddr, fshared, uaddr2, val, val2, &val3); - break; default: ret = -ENOSYS; } @@ -2460,8 +2064,7 @@ asmlinkage long sys_futex(u32 __user *uaddr, int op, u32 val, /* * requeue parameter in 'utime' if cmd == FUTEX_REQUEUE. */ - if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE - || cmd == FUTEX_CMP_REQUEUE_PI) + if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE) val2 = (u32) (unsigned long) utime; return do_futex(uaddr, op, val, tp, uaddr2, val2, val3); diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c index 27478948b31..f7921360efa 100644 --- a/kernel/futex_compat.c +++ b/kernel/futex_compat.c @@ -157,8 +157,7 @@ asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val, t = ktime_add(ktime_get(), t); tp = &t; } - if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE - || cmd == FUTEX_CMP_REQUEUE_PI) + if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE) val2 = (int) (unsigned long) utime; return do_futex(uaddr, op, val, tp, uaddr2, val2, val3); diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index a6fbb413052..17d28ce2030 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -56,7 +56,7 @@ * state. */ -void +static void rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner, unsigned long mask) { @@ -81,6 +81,29 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock) } /* + * We can speed up the acquire/release, if the architecture + * supports cmpxchg and if there's no debugging state to be set up + */ +#if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES) +# define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c) +static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) +{ + unsigned long owner, *p = (unsigned long *) &lock->owner; + + do { + owner = *p; + } while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner); +} +#else +# define rt_mutex_cmpxchg(l,c,n) (0) +static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) +{ + lock->owner = (struct task_struct *) + ((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS); +} +#endif + +/* * Calculate task priority from the waiter list priority * * Return task->normal_prio when the waiter list is empty or when @@ -100,7 +123,7 @@ int rt_mutex_getprio(struct task_struct *task) * * This can be both boosting and unboosting. task->pi_lock must be held. */ -void __rt_mutex_adjust_prio(struct task_struct *task) +static void __rt_mutex_adjust_prio(struct task_struct *task) { int prio = rt_mutex_getprio(task); @@ -136,11 +159,11 @@ int max_lock_depth = 1024; * Decreases task's usage by one - may thus free the task. * Returns 0 or -EDEADLK. */ -int rt_mutex_adjust_prio_chain(struct task_struct *task, - int deadlock_detect, - struct rt_mutex *orig_lock, - struct rt_mutex_waiter *orig_waiter, - struct task_struct *top_task) +static int rt_mutex_adjust_prio_chain(struct task_struct *task, + int deadlock_detect, + struct rt_mutex *orig_lock, + struct rt_mutex_waiter *orig_waiter, + struct task_struct *top_task) { struct rt_mutex *lock; struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter; @@ -514,8 +537,8 @@ static void wakeup_next_waiter(struct rt_mutex *lock) * * Must be called with lock->wait_lock held */ -void remove_waiter(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter) +static void remove_waiter(struct rt_mutex *lock, + struct rt_mutex_waiter *waiter) { int first = (waiter == rt_mutex_top_waiter(lock)); struct task_struct *owner = rt_mutex_owner(lock); diff --git a/kernel/rtmutex_common.h b/kernel/rtmutex_common.h index 242ec7ee740..9c75856e791 100644 --- a/kernel/rtmutex_common.h +++ b/kernel/rtmutex_common.h @@ -113,29 +113,6 @@ static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock) } /* - * We can speed up the acquire/release, if the architecture - * supports cmpxchg and if there's no debugging state to be set up - */ -#if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES) -# define rt_mutex_cmpxchg(l,c,n) (cmpxchg(&l->owner, c, n) == c) -static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) -{ - unsigned long owner, *p = (unsigned long *) &lock->owner; - - do { - owner = *p; - } while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner); -} -#else -# define rt_mutex_cmpxchg(l,c,n) (0) -static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) -{ - lock->owner = (struct task_struct *) - ((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS); -} -#endif - -/* * PI-futex support (proxy locking functions, etc.): */ extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock); @@ -143,15 +120,4 @@ 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); - -extern void rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner, - unsigned long mask); -extern void __rt_mutex_adjust_prio(struct task_struct *task); -extern int rt_mutex_adjust_prio_chain(struct task_struct *task, - int deadlock_detect, - struct rt_mutex *orig_lock, - struct rt_mutex_waiter *orig_waiter, - struct task_struct *top_task); -extern void remove_waiter(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter); #endif |