From 49994911b401c5f6b979060ffbc834949a024d8a Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 25 Sep 2024 15:31:44 +1000 Subject: [PATCH] softirq: use bit waits instead of var waits. The waiting in softirq.c is always waiting for a bit to be cleared. This makes the bit wait functions seem more suitable. By switching over we can rid of all explicit barriers. We also use wait_on_bit_lock() to avoid an explicit loop. Signed-off-by: NeilBrown Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20240925053405.3960701-8-neilb@suse.de --- kernel/softirq.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/kernel/softirq.c b/kernel/softirq.c index d082e7840f88..b756d6b3fd09 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -748,10 +748,8 @@ EXPORT_SYMBOL(__tasklet_hi_schedule); static bool tasklet_clear_sched(struct tasklet_struct *t) { - if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) { - wake_up_var(&t->state); + if (test_and_clear_wake_up_bit(TASKLET_STATE_SCHED, &t->state)) return true; - } WARN_ONCE(1, "tasklet SCHED state not set: %s %pS\n", t->use_callback ? "callback" : "func", @@ -871,8 +869,7 @@ void tasklet_kill(struct tasklet_struct *t) if (in_interrupt()) pr_notice("Attempt to kill tasklet from interrupt\n"); - while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) - wait_var_event(&t->state, !test_bit(TASKLET_STATE_SCHED, &t->state)); + wait_on_bit_lock(&t->state, TASKLET_STATE_SCHED, TASK_UNINTERRUPTIBLE); tasklet_unlock_wait(t); tasklet_clear_sched(t); @@ -882,16 +879,13 @@ EXPORT_SYMBOL(tasklet_kill); #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) void tasklet_unlock(struct tasklet_struct *t) { - smp_mb__before_atomic(); - clear_bit(TASKLET_STATE_RUN, &t->state); - smp_mb__after_atomic(); - wake_up_var(&t->state); + clear_and_wake_up_bit(TASKLET_STATE_RUN, &t->state); } EXPORT_SYMBOL_GPL(tasklet_unlock); void tasklet_unlock_wait(struct tasklet_struct *t) { - wait_var_event(&t->state, !test_bit(TASKLET_STATE_RUN, &t->state)); + wait_on_bit(&t->state, TASKLET_STATE_RUN, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL_GPL(tasklet_unlock_wait); #endif