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SubjectRe: [PATCH v2 1/3] sysfs: Support is_visible() on binary attributes
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On 09/14/2015 05:34 AM, Emilio López wrote:
> According to the sysfs header file:
>
> "The returned value will replace static permissions defined in
> struct attribute or struct bin_attribute."
>
> but this isn't the case, as is_visible is only called on struct attribute
> only. This patch introduces a new is_bin_visible() function to implement
> the same functionality for binary attributes, and updates documentation
> accordingly.
>
> Signed-off-by: Emilio López <emilio.lopez@collabora.co.uk>

Nitpick below, but otherwise looks ok to me.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Guenter

> ---
>
> Changes from v1:
> - Don't overload is_visible, introduce is_bin_visible instead as
> discussed on the list.
>
> fs/sysfs/group.c | 17 +++++++++++++++--
> include/linux/sysfs.h | 18 ++++++++++++++----
> 2 files changed, 29 insertions(+), 6 deletions(-)
>
> diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
> index 39a0199..51b56e6 100644
> --- a/fs/sysfs/group.c
> +++ b/fs/sysfs/group.c
> @@ -73,13 +73,26 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj,
> }
>
> if (grp->bin_attrs) {
> - for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
> + for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
> + umode_t mode = (*bin_attr)->attr.mode;
> +
> if (update)
> kernfs_remove_by_name(parent,
> (*bin_attr)->attr.name);
> + if (grp->is_bin_visible) {
> + mode = grp->is_bin_visible(kobj, *bin_attr, i);
> + if (!mode)
> + continue;
> + }
> +
> + WARN(mode & ~(SYSFS_PREALLOC | 0664),
> + "Attribute %s: Invalid permissions 0%o\n",
> + (*bin_attr)->attr.name, mode);
> +
> + mode &= SYSFS_PREALLOC | 0664;

Strictly speaking, the mode validation for binary attributes is new and logically
separate. Should it be mentioned in the commit log, or even be a separate patch ?

> error = sysfs_add_file_mode_ns(parent,
> &(*bin_attr)->attr, true,
> - (*bin_attr)->attr.mode, NULL);
> + mode, NULL);
> if (error)
> break;
> }
> diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> index 9f65758..2f66050 100644
> --- a/include/linux/sysfs.h
> +++ b/include/linux/sysfs.h
> @@ -64,10 +64,18 @@ do { \
> * a new subdirectory with this name.
> * @is_visible: Optional: Function to return permissions associated with an
> * attribute of the group. Will be called repeatedly for each
> - * attribute in the group. Only read/write permissions as well as
> - * SYSFS_PREALLOC are accepted. Must return 0 if an attribute is
> - * not visible. The returned value will replace static permissions
> - * defined in struct attribute or struct bin_attribute.
> + * non-binary attribute in the group. Only read/write
> + * permissions as well as SYSFS_PREALLOC are accepted. Must
> + * return 0 if an attribute is not visible. The returned value
> + * will replace static permissions defined in struct attribute.
> + * @is_bin_visible:
> + * Optional: Function to return permissions associated with a
> + * binary attribute of the group. Will be called repeatedly
> + * for each binary attribute in the group. Only read/write
> + * permissions as well as SYSFS_PREALLOC are accepted. Must
> + * return 0 if a binary attribute is not visible. The returned
> + * value will replace static permissions defined in
> + * struct bin_attribute.
> * @attrs: Pointer to NULL terminated list of attributes.
> * @bin_attrs: Pointer to NULL terminated list of binary attributes.
> * Either attrs or bin_attrs or both must be provided.
> @@ -76,6 +84,8 @@ struct attribute_group {
> const char *name;
> umode_t (*is_visible)(struct kobject *,
> struct attribute *, int);
> + umode_t (*is_bin_visible)(struct kobject *,
> + struct bin_attribute *, int);
> struct attribute **attrs;
> struct bin_attribute **bin_attrs;
> };
>



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