On Fri, Feb 14, 2020 at 09:05:17AM -0800, Minchan Kim wrote:

process_madvise syscall needs pidfd_get_pid function to translate
pidfd to pid so this patch exports the function.

For that it should not need to exported, but then again the actual
patch doesn't export it anyway, so this is just a commit log issue.

 extern struct pid *pidfd_pid(const struct file *file);
+extern struct pid *pidfd_get_pid(unsigned int fd);

... and there is no need for the extern keyword on prototypes in
headers.