xfs: rename xfs_get_perag

xfs_get_perag is really getting the perag that an inode belongs to
based on it's inode number. Convert the use of this function to just
get the perag from a provided ag number.  Use this new function to
obtain the per-ag structure when traversing the per AG inode trees
for sync and reclaim.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 1df7e45..f8a68a2 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -386,14 +386,14 @@
 /*
  * perag get/put wrappers for eventual ref counting
  */
-static inline xfs_perag_t *
-xfs_get_perag(struct xfs_mount *mp, xfs_ino_t ino)
+static inline struct xfs_perag *
+xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno)
 {
-	return &mp->m_perag[XFS_INO_TO_AGNO(mp, ino)];
+	return &mp->m_perag[agno];
 }
 
 static inline void
-xfs_put_perag(struct xfs_mount *mp, xfs_perag_t *pag)
+xfs_perag_put(struct xfs_perag *pag)
 {
 	/* nothing to see here, move along */
 }