* @uaddr: virtual address of the futex
* @fshared: 0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED
* @key: address where result is stored.
+ * @rw: mapping needs to be read/write (values: VERIFY_READ, VERIFY_WRITE)
*
* Returns a negative error code or 0
* The key words are stored in *key on success.
*
* lock_page() might sleep, the caller should not hold a spinlock.
*/
-static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
+static int
+get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
{
unsigned long address = (unsigned long)uaddr;
struct mm_struct *mm = current->mm;
* but access_ok() should be faster than find_vma()
*/
if (!fshared) {
- if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))))
+ if (unlikely(!access_ok(rw, uaddr, sizeof(u32))))
return -EFAULT;
key->private.mm = mm;
key->private.address = address;
}
again:
- err = get_user_pages_fast(address, 1, 0, &page);
+ err = get_user_pages_fast(address, 1, rw == VERIFY_WRITE, &page);
if (err < 0)
return err;
return ret ? -EFAULT : 0;
}
-/*
- * Fault handling.
- */
-static int futex_handle_fault(unsigned long address, int attempt)
-{
- struct vm_area_struct * vma;
- struct mm_struct *mm = current->mm;
- int ret = -EFAULT;
-
- if (attempt > 2)
- return ret;
-
- down_read(&mm->mmap_sem);
- vma = find_vma(mm, address);
- if (vma && address >= vma->vm_start &&
- (vma->vm_flags & VM_WRITE)) {
- int fault;
- fault = handle_mm_fault(mm, vma, address, 1);
- if (unlikely((fault & VM_FAULT_ERROR))) {
-#if 0
- /* XXX: let's do this when we verify it is OK */
- if (ret & VM_FAULT_OOM)
- ret = -ENOMEM;
-#endif
- } else {
- ret = 0;
- if (fault & VM_FAULT_MAJOR)
- current->maj_flt++;
- else
- current->min_flt++;
- }
- }
- up_read(&mm->mmap_sem);
- return ret;
-}
/*
* PI code:
static inline void
double_unlock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
{
- if (hb1 <= hb2) {
- spin_unlock(&hb2->lock);
- if (hb1 < hb2)
- spin_unlock(&hb1->lock);
- } else { /* hb1 > hb2 */
- spin_unlock(&hb1->lock);
+ spin_unlock(&hb1->lock);
+ if (hb1 != hb2)
spin_unlock(&hb2->lock);
- }
}
/*
if (!bitset)
return -EINVAL;
- ret = get_futex_key(uaddr, fshared, &key);
+ ret = get_futex_key(uaddr, fshared, &key, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
struct futex_hash_bucket *hb1, *hb2;
struct plist_head *head;
struct futex_q *this, *next;
- int ret, op_ret, attempt = 0;
+ int ret, op_ret;
-retryfull:
- ret = get_futex_key(uaddr1, fshared, &key1);
+retry:
+ ret = get_futex_key(uaddr1, fshared, &key1, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
- ret = get_futex_key(uaddr2, fshared, &key2);
+ ret = get_futex_key(uaddr2, fshared, &key2, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out_put_key1;
hb1 = hash_futex(&key1);
hb2 = hash_futex(&key2);
-retry:
double_lock_hb(hb1, hb2);
-
+retry_private:
op_ret = futex_atomic_op_inuser(op, uaddr2);
if (unlikely(op_ret < 0)) {
u32 dummy;
goto out_put_keys;
}
- /*
- * futex_atomic_op_inuser needs to both read and write
- * *(int __user *)uaddr2, but we can't modify it
- * non-atomically. Therefore, if get_user below is not
- * enough, we need to handle the fault ourselves, while
- * still holding the mmap_sem.
- */
- if (attempt++) {
- ret = futex_handle_fault((unsigned long)uaddr2,
- attempt);
- if (ret)
- goto out_put_keys;
- goto retry;
- }
-
ret = get_user(dummy, uaddr2);
if (ret)
goto out_put_keys;
+ if (!fshared)
+ goto retry_private;
+
put_futex_key(fshared, &key2);
put_futex_key(fshared, &key1);
- goto retryfull;
+ goto retry;
}
head = &hb1->chain;
int ret, drop_count = 0;
retry:
- ret = get_futex_key(uaddr1, fshared, &key1);
+ ret = get_futex_key(uaddr1, fshared, &key1, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
- ret = get_futex_key(uaddr2, fshared, &key2);
+ ret = get_futex_key(uaddr2, fshared, &key2, VERIFY_READ);
if (unlikely(ret != 0))
goto out_put_key1;
hb1 = hash_futex(&key1);
hb2 = hash_futex(&key2);
+retry_private:
double_lock_hb(hb1, hb2);
if (likely(cmpval != NULL)) {
if (unlikely(ret)) {
double_unlock_hb(hb1, hb2);
- put_futex_key(fshared, &key2);
- put_futex_key(fshared, &key1);
-
ret = get_user(curval, uaddr1);
+ if (ret)
+ goto out_put_keys;
- if (!ret)
- goto retry;
+ if (!fshared)
+ goto retry_private;
- goto out_put_keys;
+ put_futex_key(fshared, &key2);
+ put_futex_key(fshared, &key1);
+ goto retry;
}
if (curval != *cmpval) {
ret = -EAGAIN;
out_unlock:
double_unlock_hb(hb1, hb2);
- /* drop_futex_key_refs() must be called outside the spinlocks. */
+ /*
+ * drop_futex_key_refs() must be called outside the spinlocks. During
+ * the requeue we moved futex_q's from the hash bucket at key1 to the
+ * one at key2 and updated their key pointer. We no longer need to
+ * hold the references to key1.
+ */
while (--drop_count >= 0)
drop_futex_key_refs(&key1);
struct futex_pi_state *pi_state = q->pi_state;
struct task_struct *oldowner = pi_state->owner;
u32 uval, curval, newval;
- int ret, attempt = 0;
+ int ret;
/* Owner died? */
if (!pi_state->owner)
handle_fault:
spin_unlock(q->lock_ptr);
- ret = futex_handle_fault((unsigned long)uaddr, attempt++);
+ ret = get_user(uval, uaddr);
spin_lock(q->lock_ptr);
q.bitset = bitset;
retry:
q.key = FUTEX_KEY_INIT;
- ret = get_futex_key(uaddr, fshared, &q.key);
+ ret = get_futex_key(uaddr, fshared, &q.key, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
+retry_private:
hb = queue_lock(&q);
/*
if (unlikely(ret)) {
queue_unlock(&q, hb);
- put_futex_key(fshared, &q.key);
ret = get_user(uval, uaddr);
+ if (ret)
+ goto out_put_key;
- if (!ret)
- goto retry;
- goto out;
+ if (!fshared)
+ goto retry_private;
+
+ put_futex_key(fshared, &q.key);
+ goto retry;
}
ret = -EWOULDBLOCK;
if (unlikely(uval != val)) {
if (!abs_time)
schedule();
else {
- unsigned long slack;
- slack = current->timer_slack_ns;
- if (rt_task(current))
- slack = 0;
hrtimer_init_on_stack(&t.timer,
clockrt ? CLOCK_REALTIME :
CLOCK_MONOTONIC,
HRTIMER_MODE_ABS);
hrtimer_init_sleeper(&t, current);
- hrtimer_set_expires_range_ns(&t.timer, *abs_time, slack);
+ hrtimer_set_expires_range_ns(&t.timer, *abs_time,
+ current->timer_slack_ns);
hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
if (!hrtimer_active(&t.timer))
struct futex_hash_bucket *hb;
u32 uval, newval, curval;
struct futex_q q;
- int ret, lock_taken, ownerdied = 0, attempt = 0;
+ int ret, lock_taken, ownerdied = 0;
if (refill_pi_state_cache())
return -ENOMEM;
q.pi_state = NULL;
retry:
q.key = FUTEX_KEY_INIT;
- ret = get_futex_key(uaddr, fshared, &q.key);
+ ret = get_futex_key(uaddr, fshared, &q.key, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out;
-retry_unlocked:
+retry_private:
hb = queue_lock(&q);
retry_locked:
}
}
+ /*
+ * If fixup_pi_state_owner() faulted and was unable to handle the
+ * fault, unlock it and return the fault to userspace.
+ */
+ if (ret && (rt_mutex_owner(&q.pi_state->pi_mutex) == current))
+ rt_mutex_unlock(&q.pi_state->pi_mutex);
+
/* Unqueue and drop the lock */
unqueue_me_pi(&q);
*/
queue_unlock(&q, hb);
- if (attempt++) {
- ret = futex_handle_fault((unsigned long)uaddr, attempt);
- if (ret)
- goto out_put_key;
- goto retry_unlocked;
- }
-
ret = get_user(uval, uaddr);
- if (!ret)
- goto retry_unlocked;
+ if (ret)
+ goto out_put_key;
+
+ if (!fshared)
+ goto retry_private;
- goto out_put_key;
+ put_futex_key(fshared, &q.key);
+ goto retry;
}
u32 uval;
struct plist_head *head;
union futex_key key = FUTEX_KEY_INIT;
- int ret, attempt = 0;
+ int ret;
retry:
if (get_user(uval, uaddr))
if ((uval & FUTEX_TID_MASK) != task_pid_vnr(current))
return -EPERM;
- ret = get_futex_key(uaddr, fshared, &key);
+ ret = get_futex_key(uaddr, fshared, &key, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out;
hb = hash_futex(&key);
-retry_unlocked:
spin_lock(&hb->lock);
/*
* we have to drop the mmap_sem in order to call get_user().
*/
spin_unlock(&hb->lock);
-
- if (attempt++) {
- ret = futex_handle_fault((unsigned long)uaddr, attempt);
- if (ret)
- goto out;
- uval = 0;
- goto retry_unlocked;
- }
+ put_futex_key(fshared, &key);
ret = get_user(uval, uaddr);
- put_futex_key(fshared, &key);
if (!ret)
goto retry;
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff