From: Andreas Gruenbacher <agruenba@redhat.com>
Date: Mon, 27 Jan 2025 16:26:05 +0000 (+0100)
Subject: bcachefs: add eytzinger0_for_each_prev
X-Git-Tag: v6.15-rc1~146^2~120
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=dc5ceaaad81a724e7090d8709290fae36e3f2a5d;p=thirdparty%2Fkernel%2Flinux.git

bcachefs: add eytzinger0_for_each_prev

Add an eytzinger0_for_each_prev() macro for iterating through an
eytzinger array in reverse.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---

diff --git a/fs/bcachefs/eytzinger.h b/fs/bcachefs/eytzinger.h
index 5f2f96b1295ef..99edae4bb9950 100644
--- a/fs/bcachefs/eytzinger.h
+++ b/fs/bcachefs/eytzinger.h
@@ -244,6 +244,11 @@ static inline unsigned inorder_to_eytzinger0(unsigned i, unsigned size)
 	     (_i) != -1;				\
 	     (_i) = eytzinger0_next((_i), (_size)))
 
+#define eytzinger0_for_each_prev(_i, _size)		\
+	for (unsigned (_i) = eytzinger0_last((_size));	\
+	     (_i) != -1;				\
+	     (_i) = eytzinger0_prev((_i), (_size)))
+
 /* return greatest node <= @search, or -1 if not found */
 static inline int eytzinger0_find_le(void *base, size_t nr, size_t size,
 				     cmp_func_t cmp, const void *search)
diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
index 4114e5264965b..ebe3b5b1e615b 100644
--- a/fs/bcachefs/util.c
+++ b/fs/bcachefs/util.c
@@ -769,6 +769,15 @@ void eytzinger0_test(void)
 			inorder++;
 		}
 		BUG_ON(inorder != size);
+
+		inorder = size - 1;
+		eytzinger0_for_each_prev(eytz, size) {
+			BUG_ON(eytz != eytzinger0_first(size) &&
+			       eytzinger0_next(eytzinger0_prev(eytz, size), size) != eytz);
+
+			inorder--;
+		}
+		BUG_ON(inorder != -1);
 	}
 }