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Commit 1d615482 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

sched: Convert pi_lock to raw_spinlock 



Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
parent fe841226

include/linux/init_task.h

+1 −1
Original line number Diff line number Diff line
@@ -165,7 +165,7 @@ extern struct cred init_cred; 
	.journal_info	= NULL,						\

	.cpu_timers	= INIT_CPU_TIMERS(tsk.cpu_timers),		\

	.fs_excl	= ATOMIC_INIT(0),				\

	.pi_lock	= __SPIN_LOCK_UNLOCKED(tsk.pi_lock),		\

	.pi_lock	= __RAW_SPIN_LOCK_UNLOCKED(tsk.pi_lock),	\

	.timer_slack_ns = 50000, /* 50 usec default slack */		\

	.pids = {							\

		[PIDTYPE_PID]  = INIT_PID_LINK(PIDTYPE_PID),		\

include/linux/sched.h

+1 −1
Original line number Diff line number Diff line
@@ -1409,7 +1409,7 @@ struct task_struct { 
#endif



	/* Protection of the PI data structures: */

	spinlock_t pi_lock;

	raw_spinlock_t pi_lock;



#ifdef CONFIG_RT_MUTEXES

	/* PI waiters blocked on a rt_mutex held by this task */

kernel/exit.c

+1 −1
Original line number Diff line number Diff line
@@ -933,7 +933,7 @@ NORET_TYPE void do_exit(long code) 
	 * an exiting task cleaning up the robust pi futexes.

	 */

	smp_mb();

	spin_unlock_wait(&tsk->pi_lock);

	raw_spin_unlock_wait(&tsk->pi_lock);



	if (unlikely(in_atomic()))

		printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",

kernel/fork.c

+2 −2
Original line number Diff line number Diff line
@@ -939,9 +939,9 @@ SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) 


static void rt_mutex_init_task(struct task_struct *p)

{

	spin_lock_init(&p->pi_lock);

	raw_spin_lock_init(&p->pi_lock);

#ifdef CONFIG_RT_MUTEXES

	plist_head_init(&p->pi_waiters, &p->pi_lock);

	plist_head_init_raw(&p->pi_waiters, &p->pi_lock);

	p->pi_blocked_on = NULL;

#endif

}

kernel/futex.c

+19 −19
Original line number Diff line number Diff line
@@ -403,9 +403,9 @@ static void free_pi_state(struct futex_pi_state *pi_state) 
	 * and has cleaned up the pi_state already

	 */

	if (pi_state->owner) {

		spin_lock_irq(&pi_state->owner->pi_lock);

		raw_spin_lock_irq(&pi_state->owner->pi_lock);

		list_del_init(&pi_state->list);

		spin_unlock_irq(&pi_state->owner->pi_lock);

		raw_spin_unlock_irq(&pi_state->owner->pi_lock);



		rt_mutex_proxy_unlock(&pi_state->pi_mutex, pi_state->owner);

	}
@@ -470,18 +470,18 @@ void exit_pi_state_list(struct task_struct *curr) 
	 * pi_state_list anymore, but we have to be careful

	 * versus waiters unqueueing themselves:

	 */

	spin_lock_irq(&curr->pi_lock);

	raw_spin_lock_irq(&curr->pi_lock);

	while (!list_empty(head)) {



		next = head->next;

		pi_state = list_entry(next, struct futex_pi_state, list);

		key = pi_state->key;

		hb = hash_futex(&key);

		spin_unlock_irq(&curr->pi_lock);

		raw_spin_unlock_irq(&curr->pi_lock);



		spin_lock(&hb->lock);



		spin_lock_irq(&curr->pi_lock);

		raw_spin_lock_irq(&curr->pi_lock);

		/*

		 * We dropped the pi-lock, so re-check whether this

		 * task still owns the PI-state:
@@ -495,15 +495,15 @@ void exit_pi_state_list(struct task_struct *curr) 
		WARN_ON(list_empty(&pi_state->list));

		list_del_init(&pi_state->list);

		pi_state->owner = NULL;

		spin_unlock_irq(&curr->pi_lock);

		raw_spin_unlock_irq(&curr->pi_lock);



		rt_mutex_unlock(&pi_state->pi_mutex);



		spin_unlock(&hb->lock);



		spin_lock_irq(&curr->pi_lock);

		raw_spin_lock_irq(&curr->pi_lock);

	}

	spin_unlock_irq(&curr->pi_lock);

	raw_spin_unlock_irq(&curr->pi_lock);

}



static int
@@ -558,7 +558,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, 
	 * change of the task flags, we do this protected by

	 * p->pi_lock:

	 */

	spin_lock_irq(&p->pi_lock);

	raw_spin_lock_irq(&p->pi_lock);

	if (unlikely(p->flags & PF_EXITING)) {

		/*

		 * The task is on the way out. When PF_EXITPIDONE is
@@ -567,7 +567,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, 
		 */

		int ret = (p->flags & PF_EXITPIDONE) ? -ESRCH : -EAGAIN;



		spin_unlock_irq(&p->pi_lock);

		raw_spin_unlock_irq(&p->pi_lock);

		put_task_struct(p);

		return ret;

	}
@@ -586,7 +586,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, 
	WARN_ON(!list_empty(&pi_state->list));

	list_add(&pi_state->list, &p->pi_state_list);

	pi_state->owner = p;

	spin_unlock_irq(&p->pi_lock);

	raw_spin_unlock_irq(&p->pi_lock);



	put_task_struct(p);
@@ -794,16 +794,16 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this) 
		}

	}



	spin_lock_irq(&pi_state->owner->pi_lock);

	raw_spin_lock_irq(&pi_state->owner->pi_lock);

	WARN_ON(list_empty(&pi_state->list));

	list_del_init(&pi_state->list);

	spin_unlock_irq(&pi_state->owner->pi_lock);

	raw_spin_unlock_irq(&pi_state->owner->pi_lock);



	spin_lock_irq(&new_owner->pi_lock);

	raw_spin_lock_irq(&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;

	spin_unlock_irq(&new_owner->pi_lock);

	raw_spin_unlock_irq(&new_owner->pi_lock);



	spin_unlock(&pi_state->pi_mutex.wait_lock);

	rt_mutex_unlock(&pi_state->pi_mutex);
@@ -1529,18 +1529,18 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, 
	 * itself.

	 */

	if (pi_state->owner != NULL) {

		spin_lock_irq(&pi_state->owner->pi_lock);

		raw_spin_lock_irq(&pi_state->owner->pi_lock);

		WARN_ON(list_empty(&pi_state->list));

		list_del_init(&pi_state->list);

		spin_unlock_irq(&pi_state->owner->pi_lock);

		raw_spin_unlock_irq(&pi_state->owner->pi_lock);

	}



	pi_state->owner = newowner;



	spin_lock_irq(&newowner->pi_lock);

	raw_spin_lock_irq(&newowner->pi_lock);

	WARN_ON(!list_empty(&pi_state->list));

	list_add(&pi_state->list, &newowner->pi_state_list);

	spin_unlock_irq(&newowner->pi_lock);

	raw_spin_unlock_irq(&newowner->pi_lock);

	return 0;



	/*