The following commit has been merged into the locking/urgent branch of tip:

Commit-ID: f2dac39d93987f7de1e20b3988c8685523247ae2 Gitweb: https://git.kernel.org/tip/f2dac39d93987f7de1e20b3988c8685523247ae2 Author: Thomas Gleixner tglx@linutronix.de AuthorDate: Tue, 19 Jan 2021 16:26:38 +01:00 Committer: Thomas Gleixner tglx@linutronix.de CommitterDate: Tue, 26 Jan 2021 15:10:59 +01:00

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 --- kernel/futex.c | 53 ++++++++++++++++++++++++------------------------- 1 file changed, 26 insertions(+), 27 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c index a0fe63c..7a38ead 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2329,18 +2329,13 @@ 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;

@@ -2374,14 +2369,12 @@ retry: * 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; }

/* @@ -2408,8 +2401,7 @@ retry: * We raced against a concurrent self; things are * already fixed up. Nothing to do. */ - ret = 1; - goto out_unlock; + return 1; } newowner = argowner; } @@ -2440,7 +2432,6 @@ retry: * itself. */ pi_state_update_owner(pi_state, newowner); - raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);

return argowner == current;

@@ -2463,17 +2454,16 @@ handle_err:

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; }

@@ -2483,17 +2473,26 @@ handle_err: /* * 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; }