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authorHeikki Krogerus <heikki.krogerus@linux.intel.com>2021-02-04 17:17:06 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-02-05 12:08:10 +0300
commit151f6ff78cdf1d6de76e90556cfc43f1e48abe18 (patch)
tree5715e3acef48ab19021a641b7eba3c1559feec17 /include/linux/property.h
parent89451aabea5f91a6c1b6dc4c52cac4caffecbc8a (diff)
downloadlinux-151f6ff78cdf1d6de76e90556cfc43f1e48abe18.tar.xz
software node: Provide replacement for device_add_properties()
At the moment the function device_del() is calling device_remove_properties() unconditionally. That will result into the reference count of the software node attached to the device being decremented, and in most cases it will hit 0 at that point. So in practice device_del() will unregister the software node attached to the device, even if that was not the intention of the caller. Right now software nodes can not be reused or shared because of that. So device_del() can not unregister the software nodes unconditionally like that. Unfortunately some of the users of device_add_properties() are now relying on this behaviour. Because of that, and also in general, we do need a function that can offer similar behaviour where the lifetime of the software node is bound to the lifetime of the device. But it just has to be a separate function so the behaviour is optional. We can not remove the device_remove_properties() call from device_del() before we have that new function, and before we have replaced device_add_properties() calls with it in all the places that require that behaviour. This adds function device_create_managed_software_node() that can be used for exactly that purpose. Software nodes created with it are declared "managed", and separate handling for those nodes is added to the software node code. The reference count of the "managed" nodes is decremented when the device they are attached to is removed. This will not affect the other nodes that are not declared "managed". The function device_create_managed_software_node() has also one additional feature that device_add_properties() does not have. It allows the software nodes created with it to be part of a node hierarchy by taking also an optional parent node as parameter. Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Link: https://lore.kernel.org/r/20210204141711.53775-2-heikki.krogerus@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/property.h')
-rw-r--r--include/linux/property.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/property.h b/include/linux/property.h
index b0e413dc5927..dafccfce0262 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -491,4 +491,8 @@ void fwnode_remove_software_node(struct fwnode_handle *fwnode);
int device_add_software_node(struct device *dev, const struct software_node *swnode);
void device_remove_software_node(struct device *dev);
+int device_create_managed_software_node(struct device *dev,
+ const struct property_entry *properties,
+ const struct software_node *parent);
+
#endif /* _LINUX_PROPERTY_H_ */