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yaml
---
r: 137599
b: refs/heads/master
c: e4dc5b7
h: refs/heads/master
i:
  137597: 576c3cd
  137595: 0269012
  137591: fb894b1
  137583: 94c58db
  137567: 409d834
  137535: 491e6bd
  137471: 2e32a79
v: v3
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Darren Hart authored and Ingo Molnar committed Mar 12, 2009
1 parent e502a80 commit 84075fc
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Showing 2 changed files with 37 additions and 91 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: e8f6386c01a5699c115bdad10271a24076364c97
refs/heads/master: e4dc5b7a36a49eff97050894cf1b3a9a02523717
126 changes: 36 additions & 90 deletions trunk/kernel/futex.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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:
Expand Down Expand Up @@ -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;
Expand All @@ -773,9 +738,8 @@ futex_wake_op(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
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;
Expand All @@ -796,28 +760,16 @@ futex_wake_op(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
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;
Expand Down Expand Up @@ -877,6 +829,7 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
hb1 = hash_futex(&key1);
hb2 = hash_futex(&key2);

retry_private:
double_lock_hb(hb1, hb2);

if (likely(cmpval != NULL)) {
Expand All @@ -887,15 +840,16 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
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;
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -1141,7 +1095,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
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);

Expand Down Expand Up @@ -1190,6 +1144,7 @@ static int futex_wait(u32 __user *uaddr, int fshared,
if (unlikely(ret != 0))
goto out;

retry_private:
hb = queue_lock(&q);

/*
Expand All @@ -1216,13 +1171,16 @@ static int futex_wait(u32 __user *uaddr, int fshared,

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)) {
Expand Down Expand Up @@ -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;
Expand All @@ -1376,7 +1334,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
if (unlikely(ret != 0))
goto out;

retry_unlocked:
retry_private:
hb = queue_lock(&q);

retry_locked:
Expand Down Expand Up @@ -1601,18 +1559,15 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
*/
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;
}


Expand All @@ -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))
Expand All @@ -1644,7 +1599,6 @@ static int futex_unlock_pi(u32 __user *uaddr, int fshared)
goto out;

hb = hash_futex(&key);
retry_unlocked:
spin_lock(&hb->lock);

/*
Expand Down Expand Up @@ -1709,17 +1663,9 @@ static int futex_unlock_pi(u32 __user *uaddr, int fshared)
* 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;

Expand Down

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