[C/R v20][PATCH 46/96] c/r: add checkpoint operation for opened files of generic filesystems

[Matt Helsley]

On Wed, Mar 17, 2010 at 03:09:00PM -0600, Andreas Dilger wrote:

<snip> (already responded to the first part)

> >static const struct vm_operations_struct nfs_file_vm_ops = {
> >	.fault = filemap_fault,
> >	.page_mkwrite = nfs_vm_page_mkwrite,
> >+#ifdef CONFIG_CHECKPOINT
> >+	.checkpoint = filemap_checkpoint,
> >+#endif
> >};
> 
> Why is this one conditional, but the others are not?

Something like this perhaps (untested, but it should work).

    Move empty filemap_checkpoint definition
    
    This makes the operation usable in the nfs vm operation structure
    and avoids the extra #ifdef.
    
    Signed-off-by: Matt Helsley <matthltc at us.ibm.com>
    Cc: Andreas Dilger <adilger at sun.com>

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 4437ef9..c6f9090 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -578,9 +578,7 @@ out_unlock:
 static const struct vm_operations_struct nfs_file_vm_ops = {
 	.fault = filemap_fault,
 	.page_mkwrite = nfs_vm_page_mkwrite,
-#ifdef CONFIG_CHECKPOINT
 	.checkpoint = filemap_checkpoint,
-#endif
 };
 
 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 210d8e3..e9d9605 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1206,6 +1206,8 @@ extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
 #ifdef CONFIG_CHECKPOINT
 /* generic vm_area_ops exported for mapped files checkpoint */
 extern int filemap_checkpoint(struct ckpt_ctx *, struct vm_area_struct *);
+#else /* !CONFIG_CHECKPOINT */
+#define filemap_checkpoint NULL
 #endif
 
 /* mm/page-writeback.c */
diff --git a/mm/filemap.c b/mm/filemap.c
index 4ea28e6..bc98a15 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1678,8 +1678,6 @@ int filemap_restore(struct ckpt_ctx *ctx,
 	}
 	return ret;
 }
-#else /* !CONFIG_CHECKPOINT */
-#define filemap_checkpoint NULL
 #endif
 
 const struct vm_operations_struct generic_file_vm_ops = {