devpts, sunrpc, hostfs: don't bother with ->d_op

Default ->d_op being simple_dentry_operations is equivalent to leaving
it NULL and putting DCACHE_DONTCACHE into ->s_d_flags.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Author: Al Viro

fs/devpts/inode.c

@@ -381,7 +381,7 @@ static int devpts_fill_super(struct super_block *s, struct fs_context *fc)
 	s->s_blocksize_bits = 10;
 	s->s_magic = DEVPTS_SUPER_MAGIC;
 	s->s_op = &devpts_sops;
-	set_default_d_op(s, &simple_dentry_operations);
+	s->s_d_flags = DCACHE_DONTCACHE;
 	s->s_time_gran = 1;
 	fsi->sb = s;
 

fs/hostfs/hostfs_kern.c

@@ -933,7 +933,7 @@ static int hostfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_blocksize_bits = 10;
 	sb->s_magic = HOSTFS_SUPER_MAGIC;
 	sb->s_op = &hostfs_sbops;
-	set_default_d_op(sb, &simple_dentry_operations);
+	sb->s_d_flags = DCACHE_DONTCACHE;
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	err = super_setup_bdi(sb);
 	if (err)

net/sunrpc/rpc_pipe.c

@@ -1363,7 +1363,7 @@ rpc_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_blocksize_bits = PAGE_SHIFT;
 	sb->s_magic = RPCAUTH_GSSMAGIC;
 	sb->s_op = &s_ops;
-	set_default_d_op(sb, &simple_dentry_operations);
+	sb->s_d_flags = DCACHE_DONTCACHE;
 	sb->s_time_gran = 1;
 
 	inode = rpc_get_inode(sb, S_IFDIR | 0555);