forked from luck/tmp_suning_uos_patched
irq_work: Convert flags to atomic_t
We need to convert flags to atomic_t in order to later fix an ordering issue on atomic_cmpxchg() failure. This will allow us to use atomic_fetch_or(). Also clarify the nature of those flags. [ mingo: Converted two more usage site the original patch missed. ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191108160858.31665-2-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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31f4f5b495
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153bedbac2
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@ -22,7 +22,7 @@
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#define IRQ_WORK_CLAIMED (IRQ_WORK_PENDING | IRQ_WORK_BUSY)
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struct irq_work {
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unsigned long flags;
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atomic_t flags;
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struct llist_node llnode;
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void (*func)(struct irq_work *);
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};
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@ -30,11 +30,15 @@ struct irq_work {
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static inline
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void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
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{
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work->flags = 0;
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atomic_set(&work->flags, 0);
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work->func = func;
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}
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#define DEFINE_IRQ_WORK(name, _f) struct irq_work name = { .func = (_f), }
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#define DEFINE_IRQ_WORK(name, _f) struct irq_work name = { \
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.flags = ATOMIC_INIT(0), \
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.func = (_f) \
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}
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bool irq_work_queue(struct irq_work *work);
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bool irq_work_queue_on(struct irq_work *work, int cpu);
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@ -289,7 +289,7 @@ static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
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if (in_nmi()) {
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work = this_cpu_ptr(&up_read_work);
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if (work->irq_work.flags & IRQ_WORK_BUSY)
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if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY)
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/* cannot queue more up_read, fallback */
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irq_work_busy = true;
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}
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@ -29,16 +29,16 @@ static DEFINE_PER_CPU(struct llist_head, lazy_list);
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*/
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static bool irq_work_claim(struct irq_work *work)
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{
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unsigned long flags, oflags, nflags;
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int flags, oflags, nflags;
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/*
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* Start with our best wish as a premise but only trust any
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* flag value after cmpxchg() result.
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*/
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flags = work->flags & ~IRQ_WORK_PENDING;
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flags = atomic_read(&work->flags) & ~IRQ_WORK_PENDING;
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for (;;) {
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nflags = flags | IRQ_WORK_CLAIMED;
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oflags = cmpxchg(&work->flags, flags, nflags);
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oflags = atomic_cmpxchg(&work->flags, flags, nflags);
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if (oflags == flags)
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break;
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if (oflags & IRQ_WORK_PENDING)
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@ -61,7 +61,7 @@ void __weak arch_irq_work_raise(void)
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static void __irq_work_queue_local(struct irq_work *work)
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{
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/* If the work is "lazy", handle it from next tick if any */
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if (work->flags & IRQ_WORK_LAZY) {
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if (atomic_read(&work->flags) & IRQ_WORK_LAZY) {
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if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) &&
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tick_nohz_tick_stopped())
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arch_irq_work_raise();
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@ -143,7 +143,7 @@ static void irq_work_run_list(struct llist_head *list)
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{
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struct irq_work *work, *tmp;
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struct llist_node *llnode;
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unsigned long flags;
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int flags;
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BUG_ON(!irqs_disabled());
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@ -159,15 +159,15 @@ static void irq_work_run_list(struct llist_head *list)
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* to claim that work don't rely on us to handle their data
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* while we are in the middle of the func.
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*/
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flags = work->flags & ~IRQ_WORK_PENDING;
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xchg(&work->flags, flags);
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flags = atomic_read(&work->flags) & ~IRQ_WORK_PENDING;
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atomic_xchg(&work->flags, flags);
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work->func(work);
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/*
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* Clear the BUSY bit and return to the free state if
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* no-one else claimed it meanwhile.
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*/
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(void)cmpxchg(&work->flags, flags, flags & ~IRQ_WORK_BUSY);
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(void)atomic_cmpxchg(&work->flags, flags, flags & ~IRQ_WORK_BUSY);
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}
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}
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@ -199,7 +199,7 @@ void irq_work_sync(struct irq_work *work)
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{
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lockdep_assert_irqs_enabled();
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while (work->flags & IRQ_WORK_BUSY)
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while (atomic_read(&work->flags) & IRQ_WORK_BUSY)
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cpu_relax();
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}
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EXPORT_SYMBOL_GPL(irq_work_sync);
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@ -2961,7 +2961,7 @@ static void wake_up_klogd_work_func(struct irq_work *irq_work)
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static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
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.func = wake_up_klogd_work_func,
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.flags = IRQ_WORK_LAZY,
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.flags = ATOMIC_INIT(IRQ_WORK_LAZY),
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};
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void wake_up_klogd(void)
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@ -660,7 +660,7 @@ BPF_CALL_1(bpf_send_signal, u32, sig)
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return -EINVAL;
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work = this_cpu_ptr(&send_signal_work);
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if (work->irq_work.flags & IRQ_WORK_BUSY)
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if (atomic_read(&work->irq_work.flags) & IRQ_WORK_BUSY)
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return -EBUSY;
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/* Add the current task, which is the target of sending signal,
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