mm: swap: implement generic handler for swap_activate

The version of swap_activate introduced is sufficient for swap-over-NFS
but would not provide enough information to implement a generic handler.
This patch shuffles things slightly to ensure the same information is
available for aops->swap_activate() as is available to the core.

No functionality change.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 38356ab827c..c8667f8b535 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -429,6 +429,7 @@ struct kstatfs;
 struct vm_area_struct;
 struct vfsmount;
 struct cred;
+struct swap_info_struct;
 
 extern void __init inode_init(void);
 extern void __init inode_init_early(void);
@@ -640,8 +641,9 @@ struct address_space_operations {
 	int (*error_remove_page)(struct address_space *, struct page *);
 
 	/* swapfile support */
-	int (*swap_activate)(struct file *file);
-	int (*swap_deactivate)(struct file *file);
+	int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
+				sector_t *span);
+	void (*swap_deactivate)(struct file *file);
 };
 
 extern const struct address_space_operations empty_aops;