From: "Steven Rostedt (VMware)" Date: Sun, 22 Mar 2020 00:00:28 +0100 Subject: [PATCH 322/353] irq_work: Fix checking of IRQ_WORK_LAZY flag set on non PREEMPT_RT Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=50eb3f852f4931603f68d0fc6893082686f63e78 When CONFIG_PREEMPT_RT_FULL is not set, some of the checks for using lazy_list are not properly made as the IRQ_WORK_LAZY is not checked. There's two locations that need this update, so a use_lazy_list() helper function is added and used in both locations. Link: https://lore.kernel.org/r/20200321230028.GA22058@duo.ucw.cz Reported-by: Pavel Machek Signed-off-by: Steven Rostedt (VMware) --- kernel/irq_work.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/kernel/irq_work.c b/kernel/irq_work.c index 2940622da5b3..b6d9d35941ac 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -70,6 +70,12 @@ static void __irq_work_queue_local(struct irq_work *work, struct llist_head *lis arch_irq_work_raise(); } +static inline bool use_lazy_list(struct irq_work *work) +{ + return (IS_ENABLED(CONFIG_PREEMPT_RT_FULL) && !(work->flags & IRQ_WORK_HARD_IRQ)) + || (work->flags & IRQ_WORK_LAZY); +} + /* Enqueue the irq work @work on the current CPU */ bool irq_work_queue(struct irq_work *work) { @@ -81,11 +87,10 @@ bool irq_work_queue(struct irq_work *work) /* Queue the entry and raise the IPI if needed. */ preempt_disable(); - if (IS_ENABLED(CONFIG_PREEMPT_RT_FULL) && !(work->flags & IRQ_WORK_HARD_IRQ)) + if (use_lazy_list(work)) list = this_cpu_ptr(&lazy_list); else list = this_cpu_ptr(&raised_list); - __irq_work_queue_local(work, list); preempt_enable(); @@ -106,7 +111,6 @@ bool irq_work_queue_on(struct irq_work *work, int cpu) #else /* CONFIG_SMP: */ struct llist_head *list; - bool lazy_work, realtime = IS_ENABLED(CONFIG_PREEMPT_RT_FULL); /* All work should have been flushed before going offline */ WARN_ON_ONCE(cpu_is_offline(cpu)); @@ -116,10 +120,7 @@ bool irq_work_queue_on(struct irq_work *work, int cpu) return false; preempt_disable(); - - lazy_work = work->flags & IRQ_WORK_LAZY; - - if (lazy_work || (realtime && !(work->flags & IRQ_WORK_HARD_IRQ))) + if (use_lazy_list(work)) list = &per_cpu(lazy_list, cpu); else list = &per_cpu(raised_list, cpu);