xfs: add a xefi_entry helper

Add a helper to translate from the item list head to the
xfs_extent_free_item structure and use it so shorten assignments
and avoid the need for extra local variables.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Darrick J. Wong <[email protected]>

Author: Christoph Hellwig

fs/xfs/xfs_extfree_item.c

@@ -303,6 +303,11 @@ static const struct xfs_item_ops xfs_efd_item_ops = {
 	.iop_intent	= xfs_efd_item_intent,
 };
 
+static inline struct xfs_extent_free_item *xefi_entry(const struct list_head *e)
+{
+	return list_entry(e, struct xfs_extent_free_item, xefi_list);
+}
+
 /*
  * Fill the EFD with all extents from the EFI when we need to roll the
  * transaction and continue with a new EFI.
@@ -338,11 +343,8 @@ xfs_extent_free_diff_items(
 	const struct list_head		*a,
 	const struct list_head		*b)
 {
-	struct xfs_extent_free_item	*ra;
-	struct xfs_extent_free_item	*rb;
-
-	ra = container_of(a, struct xfs_extent_free_item, xefi_list);
-	rb = container_of(b, struct xfs_extent_free_item, xefi_list);
+	struct xfs_extent_free_item	*ra = xefi_entry(a);
+	struct xfs_extent_free_item	*rb = xefi_entry(b);
 
 	return ra->xefi_pag->pag_agno - rb->xefi_pag->pag_agno;
 }
@@ -444,15 +446,14 @@ xfs_extent_free_finish_item(
 	struct xfs_btree_cur		**state)
 {
 	struct xfs_owner_info		oinfo = { };
-	struct xfs_extent_free_item	*xefi;
+	struct xfs_extent_free_item	*xefi = xefi_entry(item);
 	struct xfs_efd_log_item		*efdp = EFD_ITEM(done);
 	struct xfs_mount		*mp = tp->t_mountp;
 	struct xfs_extent		*extp;
 	uint				next_extent;
 	xfs_agblock_t			agbno;
 	int				error = 0;
 
-	xefi = container_of(item, struct xfs_extent_free_item, xefi_list);
 	agbno = XFS_FSB_TO_AGBNO(mp, xefi->xefi_startblock);
 
 	oinfo.oi_owner = xefi->xefi_owner;
@@ -504,9 +505,7 @@ STATIC void
 xfs_extent_free_cancel_item(
 	struct list_head		*item)
 {
-	struct xfs_extent_free_item	*xefi;
-
-	xefi = container_of(item, struct xfs_extent_free_item, xefi_list);
+	struct xfs_extent_free_item	*xefi = xefi_entry(item);
 
 	xfs_extent_free_put_group(xefi);
 	kmem_cache_free(xfs_extfree_item_cache, xefi);
@@ -526,14 +525,13 @@ xfs_agfl_free_finish_item(
 	struct xfs_owner_info		oinfo = { };
 	struct xfs_mount		*mp = tp->t_mountp;
 	struct xfs_efd_log_item		*efdp = EFD_ITEM(done);
-	struct xfs_extent_free_item	*xefi;
+	struct xfs_extent_free_item	*xefi = xefi_entry(item);
 	struct xfs_extent		*extp;
 	struct xfs_buf			*agbp;
 	int				error;
 	xfs_agblock_t			agbno;
 	uint				next_extent;
 
-	xefi = container_of(item, struct xfs_extent_free_item, xefi_list);
 	ASSERT(xefi->xefi_blockcount == 1);
 	agbno = XFS_FSB_TO_AGBNO(mp, xefi->xefi_startblock);
 	oinfo.oi_owner = xefi->xefi_owner;