Using the optional is_visible function, it is actually possible to
either hide an attribute, or add a new permission, but not remove one.
This commit uses all the UGO bits returned by is_visible instead of
OR'ing them with the default attribute mode.
Concretely, this allows a driver to use macros like DEVICE_ATTR_RW to
set the attribute show and store functions and remove the S_IWUSR
permission in is_visible if the implementation doesn't provide a setter.
Signed-off-by: Vivien Didelot <vivien.dide...@savoirfairelinux.com>
---
fs/sysfs/group.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index 7d2a860..a8cfe03 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -41,7 +41,7 @@ static int create_files(struct kernfs_node *parent, struct
kobject *kobj,
if (grp->attrs) {
for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
- umode_t mode = 0;
+ umode_t mode = (*attr)->mode;
/*
* In update mode, we're changing the permissions or
@@ -51,13 +51,15 @@ static int create_files(struct kernfs_node *parent, struct
kobject *kobj,
if (update)
kernfs_remove_by_name(parent, (*attr)->name);
if (grp->is_visible) {
- mode = grp->is_visible(kobj, *attr, i);
- if (!mode)
+ umode_t ugo = grp->is_visible(kobj, *attr, i);
+
+ if (!(ugo & S_IRWXUGO))
continue;
+
+ mode = (mode & ~S_IRWXUGO) | (ugo & S_IRWXUGO);
}
error = sysfs_add_file_mode_ns(parent, *attr, false,
- (*attr)->mode | mode,
- NULL);
+ mode, NULL);
if (unlikely(error))
break;
}
--
2.2.2
--
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