uml: miscellaneous code cleanups

Code tidying -
	the pid field of struct irq_fd isn't used, so it is removed
     	os_set_fd_async needed to read flags before changing them, it
doesn't need a pid passed in because it can call getpid itself, and a
block of unused code needed deleting
	os_get_exec_close was unused, so it is removed
	ptrace_child called _exit for historical reasons which are no
longer valid, so just calls exit instead

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 9428d34..fdac1a5 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -127,7 +127,6 @@
 extern int os_stat_file(const char *file_name, struct uml_stat *buf);
 extern int os_stat_fd(const int fd, struct uml_stat *buf);
 extern int os_access(const char *file, int mode);
-extern int os_get_exec_close(int fd, int *close_on_exec);
 extern int os_set_exec_close(int fd);
 extern int os_ioctl_generic(int fd, unsigned int cmd, unsigned long arg);
 extern int os_get_ifname(int fd, char *namebuf);
@@ -142,7 +141,7 @@
 extern int os_file_size(const char *file, unsigned long long *size_out);
 extern int os_file_modtime(const char *file, unsigned long *modtime);
 extern int os_pipe(int *fd, int stream, int close_on_exec);
-extern int os_set_fd_async(int fd, int owner);
+extern int os_set_fd_async(int fd);
 extern int os_clear_fd_async(int fd);
 extern int os_set_fd_block(int fd, int blocking);
 extern int os_accept_connection(int fd);