Initialize procfs as a pseudo filesystem instead of raising
SB_I_NOEXEC and SB_I_NODEV by hand. This adds SB_I_PSEUDO.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alexander Mikhalitsyn <alex@amutable.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/proc/root.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/proc/root.c b/fs/proc/root.c
index 7fbbe92bf73a7..ca0e75081934f 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -17,6 +17,7 @@
 #include <linux/bitops.h>
 #include <linux/user_namespace.h>
 #include <linux/fs_context.h>
+#include <linux/pseudo_fs.h>
 #include <linux/mount.h>
 #include <linux/pid_namespace.h>
 #include <linux/fs_parser.h>
@@ -265,8 +266,6 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc)
 	if (ret)
 		return ret;
 
-	/* User space would break if executables or devices appear on proc */
-	s->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
 	s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
 	s->s_blocksize = 1024;
 	s->s_blocksize_bits = 10;
@@ -350,6 +349,7 @@ static int proc_init_fs_context(struct fs_context *fc)
 	put_user_ns(fc->user_ns);
 	fc->user_ns = get_user_ns(ctx->pid_ns->user_ns);
 	fc->fs_private = ctx;
+	fc_init_pseudo(fc);
 	fc->ops = &proc_fs_context_ops;
 	return 0;
 }

-- 
2.53.0