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@@ -23,35 +23,50 @@ static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
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int i;
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for (i = 0, attr = grp->attrs; *attr; i++, attr++)
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- if (!grp->is_visible ||
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- grp->is_visible(kobj, *attr, i))
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- sysfs_hash_and_remove(dir_sd, (*attr)->name);
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+ sysfs_hash_and_remove(dir_sd, (*attr)->name);
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}
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static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
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- const struct attribute_group *grp)
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+ const struct attribute_group *grp, int update)
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{
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struct attribute *const* attr;
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int error = 0, i;
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- for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++)
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- if (!grp->is_visible ||
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- grp->is_visible(kobj, *attr, i))
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- error |=
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- sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
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+ for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
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+ mode_t mode = 0;
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+
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+ /* in update mode, we're changing the permissions or
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+ * visibility. Do this by first removing then
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+ * re-adding (if required) the file */
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+ if (update)
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+ sysfs_hash_and_remove(dir_sd, (*attr)->name);
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+ if (grp->is_visible) {
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+ mode = grp->is_visible(kobj, *attr, i);
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+ if (!mode)
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+ continue;
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+ }
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+ error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
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+ (*attr)->mode | mode);
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+ if (unlikely(error))
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+ break;
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+ }
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if (error)
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remove_files(dir_sd, kobj, grp);
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return error;
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}
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-int sysfs_create_group(struct kobject * kobj,
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- const struct attribute_group * grp)
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+static int internal_create_group(struct kobject *kobj, int update,
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+ const struct attribute_group *grp)
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{
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struct sysfs_dirent *sd;
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int error;
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- BUG_ON(!kobj || !kobj->sd);
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+ BUG_ON(!kobj || (!update && !kobj->sd));
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+
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+ /* Updates may happen before the object has been instantiated */
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+ if (unlikely(update && !kobj->sd))
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+ return -EINVAL;
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if (grp->name) {
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error = sysfs_create_subdir(kobj, grp->name, &sd);
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@@ -60,7 +75,7 @@ int sysfs_create_group(struct kobject * kobj,
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} else
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sd = kobj->sd;
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sysfs_get(sd);
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- error = create_files(sd, kobj, grp);
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+ error = create_files(sd, kobj, grp, update);
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if (error) {
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if (grp->name)
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sysfs_remove_subdir(sd);
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@@ -69,6 +84,47 @@ int sysfs_create_group(struct kobject * kobj,
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return error;
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}
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+/**
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+ * sysfs_create_group - given a directory kobject, create an attribute group
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+ * @kobj: The kobject to create the group on
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+ * @grp: The attribute group to create
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+ *
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+ * This function creates a group for the first time. It will explicitly
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+ * warn and error if any of the attribute files being created already exist.
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+ *
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+ * Returns 0 on success or error.
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+ */
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+int sysfs_create_group(struct kobject *kobj,
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+ const struct attribute_group *grp)
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+{
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+ return internal_create_group(kobj, 0, grp);
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+}
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+
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+/**
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+ * sysfs_update_group - given a directory kobject, create an attribute group
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+ * @kobj: The kobject to create the group on
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+ * @grp: The attribute group to create
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+ *
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+ * This function updates an attribute group. Unlike
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+ * sysfs_create_group(), it will explicitly not warn or error if any
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+ * of the attribute files being created already exist. Furthermore,
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+ * if the visibility of the files has changed through the is_visible()
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+ * callback, it will update the permissions and add or remove the
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+ * relevant files.
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+ *
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+ * The primary use for this function is to call it after making a change
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+ * that affects group visibility.
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+ *
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+ * Returns 0 on success or error.
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+ */
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+int sysfs_update_group(struct kobject *kobj,
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+ const struct attribute_group *grp)
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+{
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+ return internal_create_group(kobj, 1, grp);
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+}
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+
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+
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+
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void sysfs_remove_group(struct kobject * kobj,
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const struct attribute_group * grp)
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{
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@@ -95,4 +151,5 @@ void sysfs_remove_group(struct kobject * kobj,
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EXPORT_SYMBOL_GPL(sysfs_create_group);
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+EXPORT_SYMBOL_GPL(sysfs_update_group);
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EXPORT_SYMBOL_GPL(sysfs_remove_group);
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