From fd0a68a2337b79a7bd4dad5e7d9dc726828527af Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 15 Feb 2024 19:10:01 -1000 Subject: workqueue, irq_work: Build fix for !CONFIG_IRQ_WORK 2f34d7337d98 ("workqueue: Fix queue_work_on() with BH workqueues") added irq_work usage to workqueue; however, it turns out irq_work is actually optional and the change breaks build on configuration which doesn't have CONFIG_IRQ_WORK enabled. Fix build by making workqueue use irq_work only when CONFIG_SMP and enabling CONFIG_IRQ_WORK when CONFIG_SMP is set. It's reasonable to argue that it may be better to just always enable it. However, this still saves a small bit of memory for tiny UP configs and also the least amount of change, so, for now, let's keep it conditional. Verified to do the right thing for x86_64 allnoconfig and defconfig, and aarch64 allnoconfig, allnoconfig + prink disable (SMP but nothing selects IRQ_WORK) and a modified aarch64 Kconfig where !SMP and nothing selects IRQ_WORK. v2: `depends on SMP` leads to Kconfig warnings when CONFIG_IRQ_WORK is selected by something else when !CONFIG_SMP. Use `def_bool y if SMP` instead. Signed-off-by: Tejun Heo Reported-by: Naresh Kamboju Tested-by: Anders Roxell Fixes: 2f34d7337d98 ("workqueue: Fix queue_work_on() with BH workqueues") Cc: Stephen Rothwell --- kernel/workqueue.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 04e35dbe6799..6ae441e13804 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1209,6 +1209,20 @@ static struct irq_work *bh_pool_irq_work(struct worker_pool *pool) return &per_cpu(bh_pool_irq_works, pool->cpu)[high]; } +static void kick_bh_pool(struct worker_pool *pool) +{ +#ifdef CONFIG_SMP + if (unlikely(pool->cpu != smp_processor_id())) { + irq_work_queue_on(bh_pool_irq_work(pool), pool->cpu); + return; + } +#endif + if (pool->attrs->nice == HIGHPRI_NICE_LEVEL) + raise_softirq_irqoff(HI_SOFTIRQ); + else + raise_softirq_irqoff(TASKLET_SOFTIRQ); +} + /** * kick_pool - wake up an idle worker if necessary * @pool: pool to kick @@ -1227,15 +1241,7 @@ static bool kick_pool(struct worker_pool *pool) return false; if (pool->flags & POOL_BH) { - if (likely(pool->cpu == smp_processor_id())) { - if (pool->attrs->nice == HIGHPRI_NICE_LEVEL) - raise_softirq_irqoff(HI_SOFTIRQ); - else - raise_softirq_irqoff(TASKLET_SOFTIRQ); - } else { - irq_work_queue_on(bh_pool_irq_work(pool), pool->cpu); - } - + kick_bh_pool(pool); return true; } -- cgit v1.2.3