sockfs: Get rid of getxattr iop

If we allow pseudo-filesystems created with mount_pseudo to have xattr
handlers, we can replace sockfs_getxattr with a sockfs_xattr_get handler
to use the xattr handler name parsing.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/net/socket.c b/net/socket.c
index 9b3dca6..976f7324 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -320,11 +320,38 @@
 	.d_dname  = sockfs_dname,
 };
 
+static int sockfs_xattr_get(const struct xattr_handler *handler,
+			    struct dentry *dentry, struct inode *inode,
+			    const char *suffix, void *value, size_t size)
+{
+	if (value) {
+		if (dentry->d_name.len + 1 > size)
+			return -ERANGE;
+		memcpy(value, dentry->d_name.name, dentry->d_name.len + 1);
+	}
+	return dentry->d_name.len + 1;
+}
+
+#define XATTR_SOCKPROTONAME_SUFFIX "sockprotoname"
+#define XATTR_NAME_SOCKPROTONAME (XATTR_SYSTEM_PREFIX XATTR_SOCKPROTONAME_SUFFIX)
+#define XATTR_NAME_SOCKPROTONAME_LEN (sizeof(XATTR_NAME_SOCKPROTONAME)-1)
+
+static const struct xattr_handler sockfs_xattr_handler = {
+	.name = XATTR_NAME_SOCKPROTONAME,
+	.get = sockfs_xattr_get,
+};
+
+static const struct xattr_handler *sockfs_xattr_handlers[] = {
+	&sockfs_xattr_handler,
+	NULL
+};
+
 static struct dentry *sockfs_mount(struct file_system_type *fs_type,
 			 int flags, const char *dev_name, void *data)
 {
-	return mount_pseudo(fs_type, "socket:", &sockfs_ops,
-		&sockfs_dentry_operations, SOCKFS_MAGIC);
+	return mount_pseudo_xattr(fs_type, "socket:", &sockfs_ops,
+				  sockfs_xattr_handlers,
+				  &sockfs_dentry_operations, SOCKFS_MAGIC);
 }
 
 static struct vfsmount *sock_mnt __read_mostly;
@@ -463,23 +490,6 @@
 	return NULL;
 }
 
-#define XATTR_SOCKPROTONAME_SUFFIX "sockprotoname"
-#define XATTR_NAME_SOCKPROTONAME (XATTR_SYSTEM_PREFIX XATTR_SOCKPROTONAME_SUFFIX)
-#define XATTR_NAME_SOCKPROTONAME_LEN (sizeof(XATTR_NAME_SOCKPROTONAME)-1)
-static ssize_t sockfs_getxattr(struct dentry *dentry, struct inode *inode,
-			       const char *name, void *value, size_t size)
-{
-	if (!strcmp(name, XATTR_NAME_SOCKPROTONAME)) {
-		if (value) {
-			if (dentry->d_name.len + 1 > size)
-				return -ERANGE;
-			memcpy(value, dentry->d_name.name, dentry->d_name.len + 1);
-		}
-		return dentry->d_name.len + 1;
-	}
-	return -EOPNOTSUPP;
-}
-
 static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,
 				size_t size)
 {
@@ -509,7 +519,7 @@
 }
 
 static const struct inode_operations sockfs_inode_ops = {
-	.getxattr = sockfs_getxattr,
+	.getxattr = generic_getxattr,
 	.listxattr = sockfs_listxattr,
 };