[PATCH] exportfs: handle CONFIG_EXPORTFS=m also

[Randy Dunlap]

When CONFIG_EXPORTFS=m, there are multiple build errors due to
the header <linux/exportfs.h> not handling the =m setting correctly.
Change the header file to check for CONFIG_EXPORTFS enabled at all
instead of just set =y.

Fixes: dfaf653dc415 ("exportfs: make ->encode_fh() a mandatory method for NFS export")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Chuck Lever <chuck.lever@xxxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxx>
Cc: linux-nfs@xxxxxxxxxxxxxxx
Cc: Amir Goldstein <amir73il@xxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: linux-fsdevel@xxxxxxxxxxxxxxx

---
 include/linux/exportfs.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -- a/include/linux/exportfs.h b/include/linux/exportfs.h
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -314,7 +314,7 @@ extern struct dentry *exportfs_decode_fh
 /*
  * Generic helpers for filesystems.
  */
-#ifdef CONFIG_EXPORTFS
+#if IS_ENABLED(CONFIG_EXPORTFS)
 int generic_encode_ino32_fh(struct inode *inode, __u32 *fh, int *max_len,
 			    struct inode *parent);
 #else