coredump: update coredump-related headers

Create a new header file, fs/coredump.h, which contains functions only
used by the new coredump.c.  It also moves do_coredump to the
include/linux/coredump.h header file, for consistency.

Signed-off-by: Alex Kelly <alex.page.kelly@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/coredump.h b/include/linux/coredump.h
index ba4b85a..42f9752 100644
--- a/include/linux/coredump.h
+++ b/include/linux/coredump.h
@@ -11,5 +11,10 @@
  */
 extern int dump_write(struct file *file, const void *addr, int nr);
 extern int dump_seek(struct file *file, loff_t off);
+#ifdef CONFIG_COREDUMP
+extern void do_coredump(long signr, int exit_code, struct pt_regs *regs);
+#else
+static inline void do_coredump(long signr, int exit_code, struct pt_regs *regs) {}
+#endif
 
 #endif /* _LINUX_COREDUMP_H */