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Code Issues Releases Wiki Activity

futex: Simplify fixup_pi_state_owner()

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commit f2dac39d93 upstream

Too many gotos already and an upcoming fix would make it even more
unreadable.

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>
This commit is contained in:
Thomas Gleixner 2021-01-19 16:26:38 +01:00 committed by Greg Kroah-Hartman
parent a597f12e97
commit abc4dd792f
1 changed files with 26 additions and 27 deletions
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53
kernel/futex.c
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@ -2331,18 +2331,13 @@ static void unqueue_me_pi(struct futex_q *q)
spin_unlock(q->lock_ptr);
}
static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
struct task_struct *argowner)
static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
struct task_struct *argowner)
{
struct futex_pi_state *pi_state = q->pi_state;
u32 uval, curval, newval;
struct task_struct *oldowner, *newowner;
u32 newtid;
int ret, err = 0;
lockdep_assert_held(q->lock_ptr);
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
u32 uval, curval, newval, newtid;
int err = 0;
oldowner = pi_state->owner;
@ -2376,14 +2371,12 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
* We raced against a concurrent self; things are
* already fixed up. Nothing to do.
*/
ret = 0;
goto out_unlock;
return 0;
}
if (__rt_mutex_futex_trylock(&pi_state->pi_mutex)) {
/* We got the lock. pi_state is correct. Tell caller. */
ret = 1;
goto out_unlock;
return 1;
}
/*
@ -2410,8 +2403,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
* We raced against a concurrent self; things are
* already fixed up. Nothing to do.
*/
ret = 1;
goto out_unlock;
return 1;
}
newowner = argowner;
}
@ -2442,7 +2434,6 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
* itself.
*/
pi_state_update_owner(pi_state, newowner);
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
return argowner == current;
@ -2465,17 +2456,16 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
switch (err) {
case -EFAULT:
ret = fault_in_user_writeable(uaddr);
err = fault_in_user_writeable(uaddr);
break;
case -EAGAIN:
cond_resched();
ret = 0;
err = 0;
break;
default:
WARN_ON_ONCE(1);
ret = err;
break;
}
@ -2485,17 +2475,26 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
/*
* Check if someone else fixed it for us:
*/
if (pi_state->owner != oldowner) {
ret = argowner == current;
goto out_unlock;
}
if (pi_state->owner != oldowner)
return argowner == current;
if (ret)
goto out_unlock;
/* Retry if err was -EAGAIN or the fault in succeeded */
if (!err)
goto retry;
goto retry;
return err;
}
out_unlock:
static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
struct task_struct *argowner)
{
struct futex_pi_state *pi_state = q->pi_state;
int ret;
lockdep_assert_held(q->lock_ptr);
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
ret = __fixup_pi_state_owner(uaddr, q, argowner);
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
return ret;
}