libxfs: add a bi_entry helper

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

Inspired-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/libxfs/defer_item.c b/libxfs/defer_item.c
index 680a72664746d2df443cf5fa190ec6a0a845bd0e..d19322a0b255b3aaa9dccacc8752df285096ab5b 100644 (file)
--- a/libxfs/defer_item.c
+++ b/libxfs/defer_item.c
@@ -439,6 +439,11 @@ const struct xfs_defer_op_type xfs_refcount_update_defer_type = {
 
 /* Inode Block Mapping */
 
+static inline struct xfs_bmap_intent *bi_entry(const struct list_head *e)
+{
+       return list_entry(e, struct xfs_bmap_intent, bi_list);
+}
+
 /* Sort bmap intents by inode. */
 static int
 xfs_bmap_update_diff_items(
@@ -446,11 +451,9 @@ xfs_bmap_update_diff_items(
        const struct list_head          *a,
        const struct list_head          *b)
 {
-       const struct xfs_bmap_intent    *ba;
-       const struct xfs_bmap_intent    *bb;
+       struct xfs_bmap_intent          *ba = bi_entry(a);
+       struct xfs_bmap_intent          *bb = bi_entry(b);
 
-       ba = container_of(a, struct xfs_bmap_intent, bi_list);
-       bb = container_of(b, struct xfs_bmap_intent, bi_list);
        return ba->bi_owner->i_ino - bb->bi_owner->i_ino;
 }
 
@@ -527,10 +530,9 @@ xfs_bmap_update_finish_item(
        struct list_head                *item,
        struct xfs_btree_cur            **state)
 {
-       struct xfs_bmap_intent          *bi;
+       struct xfs_bmap_intent          *bi = bi_entry(item);
        int                             error;
 
-       bi = container_of(item, struct xfs_bmap_intent, bi_list);
        error = xfs_bmap_finish_one(tp, bi);
        if (!error && bi->bi_bmap.br_blockcount > 0) {
                ASSERT(bi->bi_type == XFS_BMAP_UNMAP);
@@ -554,9 +556,7 @@ STATIC void
 xfs_bmap_update_cancel_item(
        struct list_head                *item)
 {
-       struct xfs_bmap_intent          *bi;
-
-       bi = container_of(item, struct xfs_bmap_intent, bi_list);
+       struct xfs_bmap_intent          *bi = bi_entry(item);
 
        xfs_bmap_update_put_group(bi);
        kmem_cache_free(xfs_bmap_intent_cache, bi);