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author | Thomas Gleixner <tglx@linutronix.de> | 2011-06-10 09:04:15 (GMT) |
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committer | Scott Wood <scottwood@freescale.com> | 2014-04-10 00:19:23 (GMT) |
commit | 0a13c973854b639f936c9a34a8ef5f0df5e75c79 (patch) | |
tree | 363e6507765c1e8bdea43f21187f6e8d52c64664 /kernel/rtmutex.c | |
parent | a73bde4dcfa135b3611f33157755f7acc5fa7ddf (diff) | |
download | linux-fsl-qoriq-0a13c973854b639f936c9a34a8ef5f0df5e75c79.tar.xz |
rtmutex-futex-prepare-rt.patch
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/rtmutex.c')
-rw-r--r-- | kernel/rtmutex.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 2656896..65ff892 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -68,6 +68,11 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock) clear_rt_mutex_waiters(lock); } +static int rt_mutex_real_waiter(struct rt_mutex_waiter *waiter) +{ + return waiter && waiter != PI_WAKEUP_INPROGRESS; +} + /* * We can speed up the acquire/release, if the architecture * supports cmpxchg and if there's no debugging state to be set up @@ -222,7 +227,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task, * reached or the state of the chain has changed while we * dropped the locks. */ - if (!waiter) + if (!rt_mutex_real_waiter(waiter)) goto out_unlock_pi; /* @@ -425,6 +430,23 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, int chain_walk = 0, res; raw_spin_lock_irqsave(&task->pi_lock, flags); + + /* + * In the case of futex requeue PI, this will be a proxy + * lock. The task will wake unaware that it is enqueueed on + * this lock. Avoid blocking on two locks and corrupting + * pi_blocked_on via the PI_WAKEUP_INPROGRESS + * flag. futex_wait_requeue_pi() sets this when it wakes up + * before requeue (due to a signal or timeout). Do not enqueue + * the task if PI_WAKEUP_INPROGRESS is set. + */ + if (task != current && task->pi_blocked_on == PI_WAKEUP_INPROGRESS) { + raw_spin_unlock_irqrestore(&task->pi_lock, flags); + return -EAGAIN; + } + + BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on)); + __rt_mutex_adjust_prio(task); waiter->task = task; waiter->lock = lock; @@ -449,7 +471,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, plist_add(&waiter->pi_list_entry, &owner->pi_waiters); __rt_mutex_adjust_prio(owner); - if (owner->pi_blocked_on) + if (rt_mutex_real_waiter(owner->pi_blocked_on)) chain_walk = 1; raw_spin_unlock_irqrestore(&owner->pi_lock, flags); } @@ -543,7 +565,7 @@ static void remove_waiter(struct rt_mutex *lock, } __rt_mutex_adjust_prio(owner); - if (owner->pi_blocked_on) + if (rt_mutex_real_waiter(owner->pi_blocked_on)) chain_walk = 1; raw_spin_unlock_irqrestore(&owner->pi_lock, flags); @@ -577,7 +599,8 @@ void rt_mutex_adjust_pi(struct task_struct *task) raw_spin_lock_irqsave(&task->pi_lock, flags); waiter = task->pi_blocked_on; - if (!waiter || waiter->list_entry.prio == task->prio) { + if (!rt_mutex_real_waiter(waiter) || + waiter->list_entry.prio == task->prio) { raw_spin_unlock_irqrestore(&task->pi_lock, flags); return; } |