Commit ca5f6251 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

tasklets: Provide tasklet_disable_in_atomic() 



Replacing the spin wait loops in tasklet_unlock_wait() with
wait_var_event() is not possible as a handful of tasklet_disable()
invocations are happening in atomic context. All other invocations are in
teardown paths which can sleep.

Provide tasklet_disable_in_atomic() and tasklet_unlock_spin_wait() to
convert the few atomic use cases over, which allows to change
tasklet_disable() and tasklet_unlock_wait() in a later step.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210309084241.563164193@linutronix.de
parent 6951547a

include/linux/interrupt.h

+22 −0
Original line number Diff line number Diff line
@@ -675,10 +675,21 @@ static inline void tasklet_unlock_wait(struct tasklet_struct *t) 
	while (test_bit(TASKLET_STATE_RUN, &t->state))

		cpu_relax();

}



/*

 * Do not use in new code. Waiting for tasklets from atomic contexts is

 * error prone and should be avoided.

 */

static inline void tasklet_unlock_spin_wait(struct tasklet_struct *t)

{

	while (test_bit(TASKLET_STATE_RUN, &t->state))

		cpu_relax();

}

#else

static inline int tasklet_trylock(struct tasklet_struct *t) { return 1; }

static inline void tasklet_unlock(struct tasklet_struct *t) { }

static inline void tasklet_unlock_wait(struct tasklet_struct *t) { }

static inline void tasklet_unlock_spin_wait(struct tasklet_struct *t) { }

#endif



extern void __tasklet_schedule(struct tasklet_struct *t);
@@ -703,6 +714,17 @@ static inline void tasklet_disable_nosync(struct tasklet_struct *t) 
	smp_mb__after_atomic();

}



/*

 * Do not use in new code. Disabling tasklets from atomic contexts is

 * error prone and should be avoided.

 */

static inline void tasklet_disable_in_atomic(struct tasklet_struct *t)

{

	tasklet_disable_nosync(t);

	tasklet_unlock_spin_wait(t);

	smp_mb();

}



static inline void tasklet_disable(struct tasklet_struct *t)

{

	tasklet_disable_nosync(t);