From: Minchan Kim <minchan@kernel.org>
Subject: pid: move pidfd_get_pid() to pid.c

process_madvise syscall needs pidfd_get_pid function to translate pidfd to
pid so this patch move the function to kernel/pid.c.

Link: http://lkml.kernel.org/r/20200302193630.68771-5-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200622192900.22757-3-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Alexander Duyck <redacted>
Reviewed-by: Alexander Duyck <redacted>
Acked-by: Christian Brauner <redacted>
Reviewed-by: Vlastimil Babka <redacted>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jann Horn <jannh@google.com>
Cc: Brian Geffon <redacted>
Cc: Daniel Colascione <redacted>
Cc: Joel Fernandes <redacted>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Dias <redacted>
Cc: Kirill Tkhai <redacted>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleksandr Natalenko <redacted>
Cc: Sandeep Patil <redacted>
Cc: SeongJae Park <redacted>
Cc: SeongJae Park <redacted>
Cc: Shakeel Butt <redacted>
Cc: Sonny Rao <redacted>
Cc: Tim Murray <redacted>
Cc: Christian Brauner <redacted>
Cc: <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/pid.h |    1 +
 kernel/exit.c       |   17 -----------------
 kernel/pid.c        |   17 +++++++++++++++++
 3 files changed, 18 insertions(+), 17 deletions(-)

--- a/include/linux/pid.h~pid-move-pidfd_get_pid-to-pidc
+++ a/include/linux/pid.h

@@ -77,6 +77,7 @@ extern const struct file_operations pidf
 struct file;
 
 extern struct pid *pidfd_pid(const struct file *file);
+struct pid *pidfd_get_pid(unsigned int fd);
 
 static inline struct pid *get_pid(struct pid *pid)
 {
--- a/kernel/exit.c~pid-move-pidfd_get_pid-to-pidc
+++ a/kernel/exit.c

@@ -1474,23 +1474,6 @@ end:
 	return retval;
 }
 
-static struct pid *pidfd_get_pid(unsigned int fd)
-{
-	struct fd f;
-	struct pid *pid;
-
-	f = fdget(fd);
-	if (!f.file)
-		return ERR_PTR(-EBADF);
-
-	pid = pidfd_pid(f.file);
-	if (!IS_ERR(pid))
-		get_pid(pid);
-
-	fdput(f);
-	return pid;
-}
-
 static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
 			  int options, struct rusage *ru)
 {
--- a/kernel/pid.c~pid-move-pidfd_get_pid-to-pidc
+++ a/kernel/pid.c

@@ -519,6 +519,23 @@ struct pid *find_ge_pid(int nr, struct p
 	return idr_get_next(&ns->idr, &nr);
 }
 
+struct pid *pidfd_get_pid(unsigned int fd)
+{
+	struct fd f;
+	struct pid *pid;
+
+	f = fdget(fd);
+	if (!f.file)
+		return ERR_PTR(-EBADF);
+
+	pid = pidfd_pid(f.file);
+	if (!IS_ERR(pid))
+		get_pid(pid);
+
+	fdput(f);
+	return pid;
+}
+
 /**
  * pidfd_create() - Create a new pid file descriptor.
  *

_