[PATCH] sysfs: if show/store is missing return -EIO

sysfs: if attribute does not implement show or store method
       read/write should return -EIO instead of 0 or -EINVAL.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

fs/sysfs/bin.c

@@ -25,7 +25,7 @@ fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)
 	struct kobject * kobj = to_kobj(dentry->d_parent);
 
 	if (!attr->read)
-		return -EINVAL;
+		return -EIO;
 
 	return attr->read(kobj, buffer, off, count);
 }
@@ -71,7 +71,7 @@ flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
 	struct kobject *kobj = to_kobj(dentry->d_parent);
 
 	if (!attr->write)
-		return -EINVAL;
+		return -EIO;
 
 	return attr->write(kobj, buffer, offset, count);
 }

fs/sysfs/file.c

@@ -23,7 +23,7 @@ subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
 {
 	struct subsystem * s = to_subsys(kobj);
 	struct subsys_attribute * sattr = to_sattr(attr);
-	ssize_t ret = 0;
+	ssize_t ret = -EIO;
 
 	if (sattr->show)
 		ret = sattr->show(s,page);
@@ -36,7 +36,7 @@ subsys_attr_store(struct kobject * kobj, struct attribute * attr,
 {
 	struct subsystem * s = to_subsys(kobj);
 	struct subsys_attribute * sattr = to_sattr(attr);
-	ssize_t ret = 0;
+	ssize_t ret = -EIO;
 
 	if (sattr->store)
 		ret = sattr->store(s,page,count);