Re: [patch 07/14] tasklets: Prevent tasklet_unlock_spin_wait() deadlock on RT
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2021-03-09 15:01:45
Also in:
linux-hyperv, linux-pci, linux-wireless, lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
On 2021-03-09 09:42:10 [+0100], Thomas Gleixner wrote:
tasklet_unlock_spin_wait() spin waits for the TASKLET_STATE_SCHED bit in the tasklet state to be cleared. This works on !RT nicely because the
… Could you please fold this:
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 07c7329d21aa7..1c14ccd351091 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h@@ -663,15 +663,6 @@ static inline int tasklet_trylock(struct tasklet_struct *t) void tasklet_unlock(struct tasklet_struct *t); void tasklet_unlock_wait(struct tasklet_struct *t); -/* - * 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) { }
diff --git a/kernel/softirq.c b/kernel/softirq.c
index f0074f1344402..c9adc5c462485 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c@@ -830,8 +830,8 @@ EXPORT_SYMBOL(tasklet_init); #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) /* - * Do not use in new code. There is no real reason to invoke this from - * atomic contexts. + * Do not use in new code. Waiting for tasklets from atomic contexts is + * error prone and should be avoided. */ void tasklet_unlock_spin_wait(struct tasklet_struct *t) {
--
2.30.1