linux-kernel - [PATCH v2 08/18] firmware: arm_ffa: Unregister the FF-A devices when cleaning up the partitions

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Message-Id: <20250131-ffa_updates-v2-8-544ba4e35387@arm.com>
Date: Fri, 31 Jan 2025 11:24:08 +0000
From: Sudeep Holla <sudeep.holla@....com>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Sudeep Holla <sudeep.holla@....com>, Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH v2 08/18] firmware: arm_ffa: Unregister the FF-A devices
 when cleaning up the partitions

Both the FF-A core and the bus were in a single module before the
commit 18c250bd7ed0 ("firmware: arm_ffa: Split bus and driver into distinct modules").

The arm_ffa_bus_exit() takes care of unregistering all the FF-A devices.
Now that there are 2 distinct modules, if the core driver is unloaded and
reloaded, it will end up adding duplicate FF-A devices as the previously
registered devices weren't unregistered when we cleaned up the modules.

Fix the same by unregistering all the FF-A devices on the FF-A bus during
the cleaning up of the partitions and hence the cleanup of the module.

Fixes: 18c250bd7ed0 ("firmware: arm_ffa: Split bus and driver into distinct modules")
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/firmware/arm_ffa/bus.c    | 3 ++-
 drivers/firmware/arm_ffa/driver.c | 7 ++++---
 include/linux/arm_ffa.h           | 3 +++
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/arm_ffa/bus.c b/drivers/firmware/arm_ffa/bus.c
index a90e2faa990219574ff20b8f573dbb7ca76137d9..98118823cf84969480fc25c937881f9b773a38c2 100644
--- a/drivers/firmware/arm_ffa/bus.c
+++ b/drivers/firmware/arm_ffa/bus.c
@@ -160,11 +160,12 @@ static int __ffa_devices_unregister(struct device *dev, void *data)
 	return 0;
 }
 
-static void ffa_devices_unregister(void)
+void ffa_devices_unregister(void)
 {
 	bus_for_each_dev(&ffa_bus_type, NULL, NULL,
 			 __ffa_devices_unregister);
 }
+EXPORT_SYMBOL_GPL(ffa_devices_unregister);
 
 bool ffa_device_is_valid(struct ffa_device *ffa_dev)
 {
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 54777055d54f5bf2dba1128e6a91bd1c0ece04fc..1df1c28978a5e70c31d5136e43033635c515e261 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -1495,10 +1495,8 @@ static int ffa_setup_partitions(void)
 
 	/* Allocate for the host */
 	ret = ffa_xa_add_partition_info(drv_info->vm_id);
-	if (ret) {
-		/* Already registered devices are freed on bus_exit */
+	if (ret)
 		ffa_partitions_cleanup();
-	}
 
 	return ret;
 }
@@ -1508,6 +1506,9 @@ static void ffa_partitions_cleanup(void)
 	struct ffa_dev_part_info *info;
 	unsigned long idx;
 
+	/* Clean up/free all registered devices */
+	ffa_devices_unregister();
+
 	xa_for_each(&drv_info->partition_info, idx, info) {
 		xa_erase(&drv_info->partition_info, idx);
 		kfree(info);
diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
index e8b8ae8b192ab11d5550c16fd33fa9d192b07f67..ca2ad5b0ac4309052d55dcf546d29423bbd40a67 100644
--- a/include/linux/arm_ffa.h
+++ b/include/linux/arm_ffa.h
@@ -176,6 +176,7 @@ void ffa_device_unregister(struct ffa_device *ffa_dev);
 int ffa_driver_register(struct ffa_driver *driver, struct module *owner,
 			const char *mod_name);
 void ffa_driver_unregister(struct ffa_driver *driver);
+void ffa_devices_unregister(void);
 bool ffa_device_is_valid(struct ffa_device *ffa_dev);
 
 #else
@@ -188,6 +189,8 @@ ffa_device_register(const struct ffa_partition_info *part_info,
 
 static inline void ffa_device_unregister(struct ffa_device *dev) {}
 
+static inline void ffa_devices_unregister(void) {}
+
 static inline int
 ffa_driver_register(struct ffa_driver *driver, struct module *owner,
 		    const char *mod_name)

-- 
2.34.1