Commit 9b5597af authored by Sudeep Holla's avatar Sudeep Holla
Browse files

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: default avatarSudeep Holla <sudeep.holla@kernel.org>
parent 09527e2c

drivers/firmware/arm_ffa/driver.c

+8 −5
Original line number Diff line number Diff line
@@ -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;