futex: Provide and use pi_state_update_owner()
commit c5cade200a
upstream
Updating pi_state::owner is done at several places with the same
code. Provide a function for it and use that at the obvious places.
This is also a preparation for a bug fix to avoid yet another copy of the
same code or alternatively introducing a completely unpenetratable mess of
gotos.
Originally-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
parent
65aad57cac
commit
015b6a4c25
|
@ -857,6 +857,29 @@ static struct futex_pi_state *alloc_pi_state(void)
|
||||||
return pi_state;
|
return pi_state;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static void pi_state_update_owner(struct futex_pi_state *pi_state,
|
||||||
|
struct task_struct *new_owner)
|
||||||
|
{
|
||||||
|
struct task_struct *old_owner = pi_state->owner;
|
||||||
|
|
||||||
|
lockdep_assert_held(&pi_state->pi_mutex.wait_lock);
|
||||||
|
|
||||||
|
if (old_owner) {
|
||||||
|
raw_spin_lock(&old_owner->pi_lock);
|
||||||
|
WARN_ON(list_empty(&pi_state->list));
|
||||||
|
list_del_init(&pi_state->list);
|
||||||
|
raw_spin_unlock(&old_owner->pi_lock);
|
||||||
|
}
|
||||||
|
|
||||||
|
if (new_owner) {
|
||||||
|
raw_spin_lock(&new_owner->pi_lock);
|
||||||
|
WARN_ON(!list_empty(&pi_state->list));
|
||||||
|
list_add(&pi_state->list, &new_owner->pi_state_list);
|
||||||
|
pi_state->owner = new_owner;
|
||||||
|
raw_spin_unlock(&new_owner->pi_lock);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
static void get_pi_state(struct futex_pi_state *pi_state)
|
static void get_pi_state(struct futex_pi_state *pi_state)
|
||||||
{
|
{
|
||||||
WARN_ON_ONCE(!refcount_inc_not_zero(&pi_state->refcount));
|
WARN_ON_ONCE(!refcount_inc_not_zero(&pi_state->refcount));
|
||||||
|
@ -1614,26 +1637,15 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
|
||||||
ret = -EINVAL;
|
ret = -EINVAL;
|
||||||
}
|
}
|
||||||
|
|
||||||
if (ret)
|
if (!ret) {
|
||||||
goto out_unlock;
|
/*
|
||||||
|
* This is a point of no return; once we modified the uval
|
||||||
/*
|
* there is no going back and subsequent operations must
|
||||||
* This is a point of no return; once we modify the uval there is no
|
* not fail.
|
||||||
* going back and subsequent operations must not fail.
|
*/
|
||||||
*/
|
pi_state_update_owner(pi_state, new_owner);
|
||||||
|
postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
|
||||||
raw_spin_lock(&pi_state->owner->pi_lock);
|
}
|
||||||
WARN_ON(list_empty(&pi_state->list));
|
|
||||||
list_del_init(&pi_state->list);
|
|
||||||
raw_spin_unlock(&pi_state->owner->pi_lock);
|
|
||||||
|
|
||||||
raw_spin_lock(&new_owner->pi_lock);
|
|
||||||
WARN_ON(!list_empty(&pi_state->list));
|
|
||||||
list_add(&pi_state->list, &new_owner->pi_state_list);
|
|
||||||
pi_state->owner = new_owner;
|
|
||||||
raw_spin_unlock(&new_owner->pi_lock);
|
|
||||||
|
|
||||||
postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
|
|
||||||
|
|
||||||
out_unlock:
|
out_unlock:
|
||||||
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
|
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
|
||||||
|
@ -2566,19 +2578,7 @@ retry:
|
||||||
* We fixed up user space. Now we need to fix the pi_state
|
* We fixed up user space. Now we need to fix the pi_state
|
||||||
* itself.
|
* itself.
|
||||||
*/
|
*/
|
||||||
if (pi_state->owner != NULL) {
|
pi_state_update_owner(pi_state, newowner);
|
||||||
raw_spin_lock(&pi_state->owner->pi_lock);
|
|
||||||
WARN_ON(list_empty(&pi_state->list));
|
|
||||||
list_del_init(&pi_state->list);
|
|
||||||
raw_spin_unlock(&pi_state->owner->pi_lock);
|
|
||||||
}
|
|
||||||
|
|
||||||
pi_state->owner = newowner;
|
|
||||||
|
|
||||||
raw_spin_lock(&newowner->pi_lock);
|
|
||||||
WARN_ON(!list_empty(&pi_state->list));
|
|
||||||
list_add(&pi_state->list, &newowner->pi_state_list);
|
|
||||||
raw_spin_unlock(&newowner->pi_lock);
|
|
||||||
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
|
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
|
||||||
|
|
||||||
return argowner == current;
|
return argowner == current;
|
||||||
|
|
Loading…
Reference in New Issue