Commit f85d90dd authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Greg Kroah-Hartman
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sysfs: attribute_group: allow registration of const attribute 



To be able to constify instances of struct attribute it has to be
possible to add them to struct attribute_group. The current type of the
attrs member however is not compatible with that. Introduce a union that
allows registration of both const and non-const attributes to enable a
piecewise transition. As both union member types are compatible no
logic needs to be adapted.

Technically it is now possible register a const struct attribute and
receive it as mutable pointer in the callbacks. This is a soundness
issue.  But this same soundness issue already exists today in
sysfs_create_file(). Also the struct definition and callback
implementation are always closely linked and are meant to be moved to
const in lockstep.

Similar to commit 906c508a ("sysfs: attribute_group: allow
registration of const bin_attribute")

Signed-off-by: default avatarThomas Weißschuh <linux@weissschuh.net>
Link: https://patch.msgid.link/20251029-sysfs-const-attr-prep-v5-1-ea7d745acff4@weissschuh.net


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a762f883

include/linux/sysfs.h

+4 −1
Original line number Diff line number Diff line
@@ -105,7 +105,10 @@ struct attribute_group { 
	size_t			(*bin_size)(struct kobject *,

					    const struct bin_attribute *,

					    int);

	union {

		struct attribute	**attrs;

		const struct attribute	*const *attrs_const;

	};

	const struct bin_attribute	*const *bin_attrs;

};