xattr: remove unused argument

his helpers is really just used to check for user.* xattr support so
don't make it pointlessly generic.

Reviewed-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Christian Brauner (Microsoft) <[e-mail]>

fs/nfsd/nfs4xdr.c

···
 		p = xdr_reserve_space(xdr, 4);
 		if (!p)
 			goto out_resource;
-		err = xattr_supported_namespace(d_inode(dentry),
-						XATTR_USER_PREFIX);
+		err = xattr_supports_user_prefix(d_inode(dentry));
 		*p++ = cpu_to_be32(err == 0);
 	}
 

fs/xattr.c

···
  * Look for any handler that deals with the specified namespace.
  */
 int
-xattr_supported_namespace(struct inode *inode, const char *prefix)
+xattr_supports_user_prefix(struct inode *inode)
 {
 	const struct xattr_handler **handlers = inode->i_sb->s_xattr;
 	const struct xattr_handler *handler;
-	size_t preflen;
 
 	if (!(inode->i_opflags & IOP_XATTR)) {
 		if (unlikely(is_bad_inode(inode)))
···
 		return -EOPNOTSUPP;
 	}
 
-	preflen = strlen(prefix);
-
 	for_each_xattr_handler(handlers, handler) {
-		if (!strncmp(xattr_prefix(handler), prefix, preflen))
+		if (!strncmp(xattr_prefix(handler), XATTR_USER_PREFIX,
+			     XATTR_USER_PREFIX_LEN))
 			return 0;
 	}
 
 	return -EOPNOTSUPP;
 }
-EXPORT_SYMBOL(xattr_supported_namespace);
+EXPORT_SYMBOL(xattr_supports_user_prefix);
 
 int
 __vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,

include/linux/xattr.h

···
 		       struct dentry *dentry, const char *name,
 		       char **xattr_value, size_t size, gfp_t flags);
 
-int xattr_supported_namespace(struct inode *inode, const char *prefix);
+int xattr_supports_user_prefix(struct inode *inode);
 
 static inline const char *xattr_prefix(const struct xattr_handler *handler)
 {