Btrfs-progs: pull back backref.c and fix it up

This patch pulls back backref.c, adds a couple of helpers everywhere that it
needs, and cleans up backref.c to fit in btrfs-progs.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
[removed free_some_buffers after "do not reclaim extent buffer"]
Signed-off-by: David Sterba <dsterba@suse.cz>

1 files changed, 15 insertions, 0 deletions

diff --git a/ulist.h b/ulist.h
index 2a0e948..9e0e4e0 100644
--- a/ulist.h
+++ b/ulist.h
@@ -58,6 +58,21 @@ void ulist_free(struct ulist *ulist);
 int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
 int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
 		    u64 *old_aux, gfp_t gfp_mask);
+
+/* just like ulist_add_merge() but take a pointer for the aux data */
+static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
+				      void **old_aux, gfp_t gfp_mask)
+{
+#if BITS_PER_LONG == 32
+	u64 old64 = (uintptr_t)*old_aux;
+	int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
+	*old_aux = (void *)((uintptr_t)old64);
+	return ret;
+#else
+	return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
+#endif
+}
+
 struct ulist_node *ulist_next(struct ulist *ulist,
 			      struct ulist_iterator *uiter);