From 9b5597af8bc51c25342ab11896532644b181d302 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Tue, 28 Apr 2026 19:33:27 +0100 Subject: [PATCH] firmware: arm_ffa: Avoid collapsing NPI work from different CPUs Notification pending interrupts are registered as per-CPU IRQs, but the driver queues all NPI handling through a single shared work_struct. That allows queue_work_on() calls from different CPUs to collapse onto a single pending work item even though the work function uses the CPU it runs on to fetch and handle per-CPU notifications. Move notif_pcpu_work into the per-CPU ffa_pcpu_irq state and initialize one work item per CPU. This keeps NPI handling independent per CPU and avoids losing notifications when multiple CPUs queue work concurrently. Link: https://patch.msgid.link/20260428-ffa_fixes-v2-3-8595ae450034@kernel.org Signed-off-by: Sudeep Holla --- drivers/firmware/arm_ffa/driver.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index e6a051b20cb7..4e66c7325a4e 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -87,6 +87,7 @@ static inline int ffa_to_linux_errno(int errno) struct ffa_pcpu_irq { struct ffa_drv_info *info; + struct work_struct notif_pcpu_work; }; struct ffa_drv_info { @@ -106,7 +107,6 @@ struct ffa_drv_info { unsigned int cpuhp_state; struct ffa_pcpu_irq __percpu *irq_pcpu; struct workqueue_struct *notif_pcpu_wq; - struct work_struct notif_pcpu_work; struct work_struct sched_recv_irq_work; struct xarray partition_info; DECLARE_HASHTABLE(notifier_hash, ilog2(FFA_MAX_NOTIFICATIONS)); @@ -1539,8 +1539,9 @@ ffa_self_notif_handle(u16 vcpu, bool is_per_vcpu, void *cb_data) static void notif_pcpu_irq_work_fn(struct work_struct *work) { - struct ffa_drv_info *info = container_of(work, struct ffa_drv_info, + struct ffa_pcpu_irq *pcpu = container_of(work, struct ffa_pcpu_irq, notif_pcpu_work); + struct ffa_drv_info *info = pcpu->info; ffa_self_notif_handle(smp_processor_id(), true, info); } @@ -1811,7 +1812,7 @@ static irqreturn_t notif_pend_irq_handler(int irq, void *irq_data) struct ffa_drv_info *info = pcpu->info; queue_work_on(smp_processor_id(), info->notif_pcpu_wq, - &info->notif_pcpu_work); + &pcpu->notif_pcpu_work); return IRQ_HANDLED; } @@ -1928,8 +1929,11 @@ static int ffa_init_pcpu_irq(void) if (!irq_pcpu) return -ENOMEM; - for_each_present_cpu(cpu) + for_each_present_cpu(cpu) { per_cpu_ptr(irq_pcpu, cpu)->info = drv_info; + INIT_WORK(&per_cpu_ptr(irq_pcpu, cpu)->notif_pcpu_work, + notif_pcpu_irq_work_fn); + } drv_info->irq_pcpu = irq_pcpu; @@ -1958,7 +1962,6 @@ static int ffa_init_pcpu_irq(void) } INIT_WORK(&drv_info->sched_recv_irq_work, ffa_sched_recv_irq_work_fn); - INIT_WORK(&drv_info->notif_pcpu_work, notif_pcpu_irq_work_fn); drv_info->notif_pcpu_wq = create_workqueue("ffa_pcpu_irq_notification"); if (!drv_info->notif_pcpu_wq) return -EINVAL;