bcachefs: Refactor trans->paths_allocated to be standard bitmap

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.c

@@ -1298,7 +1298,7 @@ static inline void __bch2_path_free(struct btree_trans *trans, struct btree_path
 {
 	__bch2_btree_path_unlock(trans, path);
 	btree_path_list_remove(trans, path);
-	trans->paths_allocated &= ~(1ULL << path->idx);
+	__clear_bit(path->idx, trans->paths_allocated);
 }
 
 void bch2_path_put(struct btree_trans *trans, struct btree_path *path, bool intent)
@@ -1471,6 +1471,7 @@ static void bch2_trans_update_max_paths(struct btree_trans *trans)
 {
 	struct btree_transaction_stats *s = btree_trans_stats(trans);
 	struct printbuf buf = PRINTBUF;
+	size_t nr = bitmap_weight(trans->paths_allocated, BTREE_ITER_MAX);
 
 	if (!s)
 		return;
@@ -1479,9 +1480,8 @@ static void bch2_trans_update_max_paths(struct btree_trans *trans)
 
 	if (!buf.allocation_failure) {
 		mutex_lock(&s->lock);
-		if (s->nr_max_paths < hweight64(trans->paths_allocated)) {
-			s->nr_max_paths = trans->nr_max_paths =
-				hweight64(trans->paths_allocated);
+		if (nr > s->nr_max_paths) {
+			s->nr_max_paths = nr;
 			swap(s->max_paths_text, buf.buf);
 		}
 		mutex_unlock(&s->lock);
@@ -1489,7 +1489,7 @@ static void bch2_trans_update_max_paths(struct btree_trans *trans)
 
 	printbuf_exit(&buf);
 
-	trans->nr_max_paths = hweight64(trans->paths_allocated);
+	trans->nr_max_paths = nr;
 }
 
 noinline __cold
@@ -1518,13 +1518,12 @@ static inline struct btree_path *btree_path_alloc(struct btree_trans *trans,
 						  struct btree_path *pos)
 {
 	struct btree_path *path;
-	unsigned idx;
+	size_t idx = find_first_zero_bit(trans->paths_allocated, BTREE_ITER_MAX);
 
-	if (unlikely(trans->paths_allocated ==
-		     ~((~0ULL << 1) << (BTREE_ITER_MAX - 1))))
+	if (unlikely(idx == BTREE_ITER_MAX))
 		btree_path_overflow(trans);
 
-	idx = __ffs64(~trans->paths_allocated);
+	BUG_ON(idx > BTREE_ITER_MAX);
 
 	/*
 	 * Do this before marking the new path as allocated, since it won't be
@@ -1533,7 +1532,7 @@ static inline struct btree_path *btree_path_alloc(struct btree_trans *trans,
 	if (unlikely(idx > trans->nr_max_paths))
 		bch2_trans_update_max_paths(trans);
 
-	trans->paths_allocated |= 1ULL << idx;
+	__set_bit(idx, trans->paths_allocated);
 
 	path = &trans->paths[idx];
 	path->idx		= idx;
@@ -2516,7 +2515,7 @@ static void btree_trans_verify_sorted_refs(struct btree_trans *trans)
 	struct btree_path *path;
 	unsigned i;
 
-	BUG_ON(trans->nr_sorted != hweight64(trans->paths_allocated));
+	BUG_ON(trans->nr_sorted != bitmap_weight(trans->paths_allocated, BTREE_ITER_MAX));
 
 	trans_for_each_path(trans, path) {
 		BUG_ON(path->sorted_idx >= trans->nr_sorted);
@@ -2526,7 +2525,7 @@ static void btree_trans_verify_sorted_refs(struct btree_trans *trans)
 	for (i = 0; i < trans->nr_sorted; i++) {
 		unsigned idx = trans->sorted[i];
 
-		EBUG_ON(!(trans->paths_allocated & (1ULL << idx)));
+		BUG_ON(!test_bit(idx, trans->paths_allocated));
 		BUG_ON(trans->paths[idx].sorted_idx != i);
 	}
 }

fs/bcachefs/btree_iter.h

@@ -66,17 +66,10 @@ static inline void btree_trans_sort_paths(struct btree_trans *trans)
 static inline struct btree_path *
 __trans_next_path(struct btree_trans *trans, unsigned idx)
 {
-	u64 l;
-
+	idx = find_next_bit(trans->paths_allocated, BTREE_ITER_MAX, idx);
 	if (idx == BTREE_ITER_MAX)
 		return NULL;
-
-	l = trans->paths_allocated >> idx;
-	if (!l)
-		return NULL;
-
-	idx += __ffs64(l);
-	EBUG_ON(idx >= BTREE_ITER_MAX);
+	EBUG_ON(idx > BTREE_ITER_MAX);
 	EBUG_ON(trans->paths[idx].idx != idx);
 	return &trans->paths[idx];
 }
@@ -92,17 +85,11 @@ __trans_next_path(struct btree_trans *trans, unsigned idx)
 static inline struct btree_path *
 __trans_next_path_safe(struct btree_trans *trans, unsigned *idx)
 {
-	u64 l;
-
+	*idx = find_next_bit(trans->paths_allocated, BTREE_ITER_MAX, *idx);
 	if (*idx == BTREE_ITER_MAX)
 		return NULL;
 
-	l = trans->paths_allocated >> *idx;
-	if (!l)
-		return NULL;
-
-	*idx += __ffs64(l);
-	EBUG_ON(*idx >= BTREE_ITER_MAX);
+	EBUG_ON(*idx > BTREE_ITER_MAX);
 	return &trans->paths[*idx];
 }
 
@@ -631,7 +618,7 @@ int __bch2_btree_trans_too_many_iters(struct btree_trans *);
 
 static inline int btree_trans_too_many_iters(struct btree_trans *trans)
 {
-	if (hweight64(trans->paths_allocated) > BTREE_ITER_MAX - 8)
+	if (bitmap_weight(trans->paths_allocated, BTREE_ITER_MAX) > BTREE_ITER_MAX - 8)
 		return __bch2_btree_trans_too_many_iters(trans);
 
 	return 0;

fs/bcachefs/btree_locking.h

@@ -263,7 +263,7 @@ static inline int btree_node_lock(struct btree_trans *trans,
 	int ret = 0;
 
 	EBUG_ON(level >= BTREE_MAX_DEPTH);
-	EBUG_ON(!(trans->paths_allocated & (1ULL << path->idx)));
+	EBUG_ON(!test_bit(path->idx, trans->paths_allocated));
 
 	if (likely(six_trylock_type(&b->lock, type)) ||
 	    btree_node_lock_increment(trans, b, level, (enum btree_node_locked_type) type) ||

fs/bcachefs/btree_types.h

@@ -414,7 +414,7 @@ struct btree_trans {
 	unsigned		extra_journal_res;
 	unsigned		nr_max_paths;
 
-	u64			paths_allocated;
+	unsigned long		paths_allocated[BITS_TO_LONGS(BTREE_ITER_MAX)];
 
 	unsigned		mem_top;
 	unsigned		mem_max;