linux-kernel - [PATCH 4/4] firmware: arm_ffa: Fix FFA notifications cleanup path

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Date:   Tue, 24 Oct 2023 11:56:20 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Sudeep Holla <sudeep.holla@....com>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        Coboy Chen <coboy.chen@...iatek.com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>
Subject: [PATCH 4/4] firmware: arm_ffa: Fix FFA notifications cleanup path

We allow the FF-A to be initialised successfully even when notification
fails. When the notification fails, ffa_notifications_cleanup() gets
called on the failure path.

However, the driver information about the notifications like the irq,
workqueues and cpu hotplug state for enabling and disabling percpu IRQ
are not cleared. This may result in unexpected behaviour during CPU
hotplug because of percpu IRQ being enabled and disabled or during the
driver removal when ffa_notifications_cleanup() gets executed again.

Fix the FFA notifications cleanup path by clearing all the notification
related driver information.

Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/firmware/arm_ffa/driver.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index b097452597a2..e636181694aa 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -1326,8 +1326,10 @@ static int ffa_sched_recv_irq_map(void)
 
 static void ffa_sched_recv_irq_unmap(void)
 {
-	if (drv_info->sched_recv_irq)
+	if (drv_info->sched_recv_irq) {
 		irq_dispose_mapping(drv_info->sched_recv_irq);
+		drv_info->sched_recv_irq = 0;
+	}
 }
 
 static int ffa_cpuhp_pcpu_irq_enable(unsigned int cpu)
@@ -1344,17 +1346,23 @@ static int ffa_cpuhp_pcpu_irq_disable(unsigned int cpu)
 
 static void ffa_uninit_pcpu_irq(void)
 {
-	if (drv_info->cpuhp_state)
+	if (drv_info->cpuhp_state) {
 		cpuhp_remove_state(drv_info->cpuhp_state);
+		drv_info->cpuhp_state = 0;
+	}
 
-	if (drv_info->notif_pcpu_wq)
+	if (drv_info->notif_pcpu_wq) {
 		destroy_workqueue(drv_info->notif_pcpu_wq);
+		drv_info->notif_pcpu_wq = NULL;
+	}
 
 	if (drv_info->sched_recv_irq)
 		free_percpu_irq(drv_info->sched_recv_irq, drv_info->irq_pcpu);
 
-	if (drv_info->irq_pcpu)
+	if (drv_info->irq_pcpu) {
 		free_percpu(drv_info->irq_pcpu);
+		drv_info->irq_pcpu = NULL;
+	}
 }
 
 static int ffa_init_pcpu_irq(unsigned int irq)

-- 
2.42.0