sysfs: add support for binary attributes in groups

groups should be able to support binary attributes, just like it
supports "normal" attributes.  This lets us only handle one type of
structure, groups, throughout the driver core and subsystems, making
binary attributes a "full fledged" part of the driver model, and not
something just "tacked on".

Reported-by: Oliver Schinagl <oliver@schinagl.nl>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 48 insertions, 22 deletions

diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index aec3d5c98c94..e5719c6095c3 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -20,38 +20,64 @@ static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
                          const struct attribute_group *grp)
 {
         struct attribute *const* attr;
-        int i;
+        struct bin_attribute *const* bin_attr;
 
-        for (i = 0, attr = grp->attrs; *attr; i++, attr++)
-                sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
+        if (grp->attrs)
+                for (attr = grp->attrs; *attr; attr++)
+                        sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
+        if (grp->bin_attrs)
+                for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
+                        sysfs_remove_bin_file(kobj, *bin_attr);
 }
 
 static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
                         const struct attribute_group *grp, int update)
 {
         struct attribute *const* attr;
+        struct bin_attribute *const* bin_attr;
         int error = 0, i;
 
-        for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
-                umode_t mode = 0;
+        if (grp->attrs) {
+                for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
+                        umode_t mode = 0;
+
+                        /*
+                         * In update mode, we're changing the permissions or
+                         * visibility.  Do this by first removing then
+                         * re-adding (if required) the file.
+                         */
+                        if (update)
+                                sysfs_hash_and_remove(dir_sd, NULL,
+                                                      (*attr)->name);
+                        if (grp->is_visible) {
+                                mode = grp->is_visible(kobj, *attr, i);
+                                if (!mode)
+                                        continue;
+                        }
+                        error = sysfs_add_file_mode(dir_sd, *attr,
+                                                    SYSFS_KOBJ_ATTR,
+                                                    (*attr)->mode | mode);
+                        if (unlikely(error))
+                                break;
+                }
+                if (error) {
+                        remove_files(dir_sd, kobj, grp);
+                        goto exit;
+                }
+        }
 
-                /* in update mode, we're changing the permissions or
-                 * visibility.  Do this by first removing then
-                 * re-adding (if required) the file */
-                if (update)
-                        sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
-                if (grp->is_visible) {
-                        mode = grp->is_visible(kobj, *attr, i);
-                        if (!mode)
-                                continue;
+        if (grp->bin_attrs) {
+                for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
+                        if (update)
+                                sysfs_remove_bin_file(kobj, *bin_attr);
+                        error = sysfs_create_bin_file(kobj, *bin_attr);
+                        if (error)
+                                break;
                 }
-                error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
-                                            (*attr)->mode | mode);
-                if (unlikely(error))
-                        break;
+                if (error)
+                        remove_files(dir_sd, kobj, grp);
         }
-        if (error)
-                remove_files(dir_sd, kobj, grp);
+exit:
         return error;
 }
 
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index d50a96b9bb6d..2c3b6a30697d 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -21,6 +21,7 @@
 
 struct kobject;
 struct module;
+struct bin_attribute;
 enum kobj_ns_type;
 
 struct attribute {
@@ -59,10 +60,9 @@ struct attribute_group {
         umode_t                 (*is_visible)(struct kobject *,
                                               struct attribute *, int);
         struct attribute        **attrs;
+        struct bin_attribute    **bin_attrs;
 };
 
-
-
 /**
  * Use these macros to make defining attributes easier. See include/linux/device.h
  * for examples..