#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)
/*
/* 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;
};
/*
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.
*
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);
return ret;
}
-/*
- * 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:
while (!ret) {
newval = (uval & FUTEX_OWNER_DIED) | newtid;
- newval |= (uval & FUTEX_WAITER_REQUEUED);
pagefault_disable();
curval = futex_atomic_cmpxchg_inatomic(uaddr,
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;
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);
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;
* 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;
}
-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:
* 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;
}
/*
* 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;
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
* 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)
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;
}
/*
* 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);
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