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futex: Simplify fixup_pi_state_owner() 

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
master
Thomas Gleixner 2021-01-19 16:26:38 +01:00
parent 6ccc84f917
commit f2dac39d93
1 changed files with 26 additions and 27 deletions
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53
kernel/futex.c
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@ -2329,18 +2329,13 @@ static void unqueue_me_pi(struct futex_q *q)
spin_unlock(q->lock_ptr); spin_unlock(q->lock_ptr);
} }
static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
struct task_struct *argowner) struct task_struct *argowner)
{ {
struct futex_pi_state *pi_state = q->pi_state; struct futex_pi_state *pi_state = q->pi_state;
u32 uval, curval, newval;
struct task_struct *oldowner, *newowner; struct task_struct *oldowner, *newowner;
u32 newtid; u32 uval, curval, newval, newtid;
int ret, err = 0; int err = 0;
lockdep_assert_held(q->lock_ptr);
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
oldowner = pi_state->owner; oldowner = pi_state->owner;
@ -2374,14 +2369,12 @@ retry:
* We raced against a concurrent self; things are * We raced against a concurrent self; things are
* already fixed up. Nothing to do. * already fixed up. Nothing to do.
*/ */
ret = 0; return 0;
goto out_unlock;
} }
if (__rt_mutex_futex_trylock(&pi_state->pi_mutex)) { if (__rt_mutex_futex_trylock(&pi_state->pi_mutex)) {
/* We got the lock. pi_state is correct. Tell caller. */ /* We got the lock. pi_state is correct. Tell caller. */
ret = 1; return 1;
goto out_unlock;
} }
/* /*
@ -2408,8 +2401,7 @@ retry:
* We raced against a concurrent self; things are * We raced against a concurrent self; things are
* already fixed up. Nothing to do. * already fixed up. Nothing to do.
*/ */
ret = 1; return 1;
goto out_unlock;
} }
newowner = argowner; newowner = argowner;
} }
@ -2440,7 +2432,6 @@ retry:
* itself. * itself.
*/ */
pi_state_update_owner(pi_state, newowner); pi_state_update_owner(pi_state, newowner);
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
return argowner == current; return argowner == current;
@ -2463,17 +2454,16 @@ handle_err:
switch (err) { switch (err) {
case -EFAULT: case -EFAULT:
ret = fault_in_user_writeable(uaddr); err = fault_in_user_writeable(uaddr);
break; break;
case -EAGAIN: case -EAGAIN:
cond_resched(); cond_resched();
ret = 0; err = 0;
break; break;
default: default:
WARN_ON_ONCE(1); WARN_ON_ONCE(1);
ret = err;
break; break;
} }
@ -2483,17 +2473,26 @@ handle_err:
/* /*
* Check if someone else fixed it for us: * Check if someone else fixed it for us:
*/ */
if (pi_state->owner != oldowner) { if (pi_state->owner != oldowner)
ret = argowner == current; return argowner == current;
goto out_unlock;
}
if (ret) /* Retry if err was -EAGAIN or the fault in succeeded */
goto out_unlock; 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); raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
return ret; return ret;
} }