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driver core: platform: amend the API contract for fwnode setters

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Calling platform_device_set_fwnode() (and by extension:
platform_device_set_of_node()) of platform_device_set_of_node_from_dev()
for a dynamically allocated platform device whose primary firmware node
is already assigned and is a software node leads to a resource leak as we
never perform the corresponding call to software_node_notify_remove(). As
there are currently no users for this special case - just disallow it and
warn loudly if it ever happens.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260716-swnode-remove-on-dev-unreg-v8-1-5c2b8cc38c28@oss.qualcomm.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Bartosz Golaszewski 2026-07-16 14:31:36 +02:00 committed by Danilo Krummrich
parent 4e63c0582e
commit e6054f410c
1 changed files with 18 additions and 3 deletions
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21
drivers/base/platform.c
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@ -707,7 +707,9 @@ EXPORT_SYMBOL_GPL(platform_device_add_data);
*
* Assign an OF node to this platform device. Internally keep track of the
* reference count. Devices created with platform_device_alloc() must use this
* function instead of assigning the node manually.
* function instead of assigning the node manually. This function must not be
* called for a platform device that already has a software node as its primary
* firmware node assigned.
*/
void platform_device_set_of_node(struct platform_device *pdev,
struct device_node *np)
@ -723,11 +725,20 @@ EXPORT_SYMBOL_GPL(platform_device_set_of_node);
*
* Assign a firmware node to this platform device. Internally keep track of the
* reference count. Devices created with platform_device_alloc() must use this
* function instead of assigning the node manually.
* function instead of assigning the node manually. This function must not be
* called for a platform device that already has a software node as its primary
* firmware node assigned.
*/
void platform_device_set_fwnode(struct platform_device *pdev,
struct fwnode_handle *fwnode)
{
/*
* If we call this function for a platform device whose primary
* firmware node is a software node, we'll never end up calling the
* symmetric software_node_notify_remove(). There are no users for this
* right now in the tree so just disallow it.
*/
WARN_ON(is_software_node(dev_fwnode(&pdev->dev)));
fwnode_handle_put(pdev->dev.fwnode);
device_set_node(&pdev->dev, fwnode_handle_get(fwnode));
}
@ -739,11 +750,15 @@ EXPORT_SYMBOL_GPL(platform_device_set_fwnode);
* @dev2: device whose OF node to reuse
*
* Reuses the OF node of another device in this platform device while
* internally keeping track of reference counting.
* internally keeping track of reference counting. This function must not be
* called for a platform device that already has a software node as its primary
* firmware node assigned.
*/
void platform_device_set_of_node_from_dev(struct platform_device *pdev,
const struct device *dev2)
{
/* See platform_device_set_fwnode(). */
WARN_ON(is_software_node(dev_fwnode(&pdev->dev)));
device_set_of_node_from_dev(&pdev->dev, dev2);
pdev->dev.fwnode = of_fwnode_handle(pdev->dev.of_node);
}