make get_unused_fd_flags() a function

... and get_unused_fd() a macro around it
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/file.c

@@ -477,8 +477,8 @@ int alloc_fd(unsigned start, unsigned flags)
 	return error;
 }
 
-int get_unused_fd(void)
+int get_unused_fd_flags(unsigned flags)
 {
-	return alloc_fd(0, 0);
+	return alloc_fd(0, flags);
 }
-EXPORT_SYMBOL(get_unused_fd);
+EXPORT_SYMBOL(get_unused_fd_flags);

include/linux/file.h

@@ -33,8 +33,8 @@ extern struct file *fget_raw_light(unsigned int fd, int *fput_needed);
 extern void set_close_on_exec(unsigned int fd, int flag);
 extern void put_filp(struct file *);
 extern int alloc_fd(unsigned start, unsigned flags);
-extern int get_unused_fd(void);
-#define get_unused_fd_flags(flags) alloc_fd(0, (flags))
+extern int get_unused_fd_flags(unsigned flags);
+#define get_unused_fd() get_unused_fd_flags(0)
 extern void put_unused_fd(unsigned int fd);
 
 extern void fd_install(unsigned int fd, struct file *file);