xfs: remove iomap_delta

The iomap_delta field in struct xfs_iomap just contains the
difference between the offset passed to xfs_iomap and the
iomap_offset.  Just calculate it in the only caller that cares.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

fs/xfs/linux-2.6/xfs_aops.c

@@ -1512,9 +1512,11 @@ __xfs_get_blocks(
 	}
 
 	if (direct || size > (1 << inode->i_blkbits)) {
-		ASSERT(iomap.iomap_bsize - iomap.iomap_delta > 0);
+		xfs_off_t iomap_delta = offset - iomap.iomap_offset;
+
+		ASSERT(iomap.iomap_bsize - iomap_delta > 0);
 		offset = min_t(xfs_off_t,
-				iomap.iomap_bsize - iomap.iomap_delta, size);
+				iomap.iomap_bsize - iomap_delta, size);
 		bh_result->b_size = (ssize_t)min_t(xfs_off_t, LONG_MAX, offset);
 	}
 

fs/xfs/xfs_iomap.c

@@ -68,7 +68,6 @@ xfs_imap_to_bmap(
 	xfs_fsblock_t	start_block;
 
 	iomapp->iomap_offset = XFS_FSB_TO_B(mp, imap->br_startoff);
-	iomapp->iomap_delta = offset - iomapp->iomap_offset;
 	iomapp->iomap_bsize = XFS_FSB_TO_B(mp, imap->br_blockcount);
 	iomapp->iomap_flags = flags;
 

fs/xfs/xfs_iomap.h

@@ -72,7 +72,6 @@ typedef struct xfs_iomap {
 	xfs_daddr_t		iomap_bn;	/* first 512B blk of mapping */
 	xfs_off_t		iomap_offset;	/* offset of mapping, bytes */
 	xfs_off_t		iomap_bsize;	/* size of mapping, bytes */
-	xfs_off_t		iomap_delta;	/* offset into mapping, bytes */
 	iomap_flags_t		iomap_flags;
 } xfs_iomap_t;