bcachefs: simplify eytzinger0_find_le

Replace the over-complicated implementation of eytzinger0_find_le() by
an equivalent, simpler version.

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 08256fcaeeb715f66045c97e94a86bd5c5f1161e..a530dbcde476c90d8a51c453ba95a4956108babc 100644 (file)
--- a/fs/bcachefs/eytzinger.h
+++ b/fs/bcachefs/eytzinger.h
@@ -254,26 +254,12 @@ static inline int eytzinger0_find_le(void *base, size_t nr, size_t size,
                                     cmp_func_t cmp, const void *search)
 {
        void *base1 = base - size;
-       unsigned i, n = 1;
-
-       if (!nr)
-               return -1;
-
-       do {
-               i = n;
-               n = eytzinger1_child(i, cmp(base1 + i * size, search) <= 0);
-       } while (n <= nr);
-
-       if (!(n & 1)) {
-               /*
-                * @i was greater than @search, return previous node:
-                *
-                * if @i was leftmost/smallest element,
-                * eytzinger1_prev(eytzinger1_first())) returns 0, as expected
-                */
-               i = eytzinger1_prev(i, nr);
-       }
-       return i - 1;
+       unsigned n = 1;
+
+       while (n <= nr)
+               n = eytzinger1_child(n, cmp(base1 + n * size, search) <= 0);
+       n >>= __ffs(n) + 1;
+       return n - 1;
 }
 
 static inline int eytzinger0_find_gt(void *base, size_t nr, size_t size,