Hi all,

After merging the pidfd tree, today's linux-next build (x86_64
allnoconfig) failed like this:

fs/nsfs.c:232:6: error: redefinition of 'proc_ns_file'
  232 | bool proc_ns_file(const struct file *file)
      |      ^~~~~~~~~~~~
In file included from fs/nsfs.c:6:
include/linux/proc_fs.h:194:20: note: previous definition of 'proc_ns_file' was here
  194 | static inline bool proc_ns_file(const struct file *file)
      |                    ^~~~~~~~~~~~

Caused by commit

  1e76b8ad203a ("nsproxy: attach to namespaces via pidfds")

I have applied the following hack for today:

From 07065344c6fb39c440b0de5f75842066bc97a675 Mon Sep 17 00:00:00 2001
From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Tue, 12 May 2020 20:08:51 +1000
Subject: [PATCH] nsproxy: protect proc_ns_file() when CONFIG_PROC_FS is not set

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---
 fs/nsfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nsfs.c b/fs/nsfs.c
index 800c1d0eb0d0..9215ad7597d6 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -229,10 +229,12 @@ int ns_get_name(char *buf, size_t size, struct task_struct *task,
 	return res;
 }
 
+#ifdef CONFIG_PROC_FS
 bool proc_ns_file(const struct file *file)
 {
 	return file->f_op == &ns_file_operations;
 }
+#endif
 
 struct file *proc_ns_fget(int fd)
 {
-- 
2.26.2

-- 
Cheers,
Stephen Rothwell