diff options
| -rw-r--r-- | kernel/futex.c | 126 |
1 files changed, 36 insertions, 90 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index c980a556f82c..9c97f67d298e 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -298,41 +298,6 @@ static int get_futex_value_locked(u32 *dest, u32 __user *from) 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: @@ -760,9 +725,9 @@ futex_wake_op(u32 __user *uaddr1, int fshared, u32 __user *uaddr2, 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: +retry: ret = get_futex_key(uaddr1, fshared, &key1); if (unlikely(ret != 0)) goto out; @@ -773,9 +738,8 @@ retryfull: 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; @@ -796,28 +760,16 @@ retry: 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; @@ -877,6 +829,7 @@ retry: hb1 = hash_futex(&key1); hb2 = hash_futex(&key2); +retry_private: double_lock_hb(hb1, hb2); if (likely(cmpval != NULL)) { @@ -887,15 +840,16 @@ retry: 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; @@ -1070,7 +1024,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, 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) @@ -1141,7 +1095,7 @@ retry: 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); @@ -1190,6 +1144,7 @@ retry: if (unlikely(ret != 0)) goto out; +retry_private: hb = queue_lock(&q); /* @@ -1216,13 +1171,16 @@ retry: 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)) { @@ -1356,7 +1314,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, 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; @@ -1376,7 +1334,7 @@ retry: if (unlikely(ret != 0)) goto out; -retry_unlocked: +retry_private: hb = queue_lock(&q); retry_locked: @@ -1601,18 +1559,15 @@ uaddr_faulted: */ 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; - goto out_put_key; + if (!fshared) + goto retry_private; + + put_futex_key(fshared, &q.key); + goto retry; } @@ -1628,7 +1583,7 @@ static int futex_unlock_pi(u32 __user *uaddr, int fshared) 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)) @@ -1644,7 +1599,6 @@ retry: goto out; hb = hash_futex(&key); -retry_unlocked: spin_lock(&hb->lock); /* @@ -1709,17 +1663,9 @@ pi_faulted: * 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; |