bpf: htab: extract helper for freeing special structs

Extract the cleanup of known embedded structs into the dedicated helper.
Remove duplication and introduce a single source of truth for freeing
special embedded structs in hashtab.

Signed-off-by: Mykyta Yatsenko <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Acked-by: Eduard Zingerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: mykyta5

kernel/bpf/hashtab.c

@@ -215,6 +215,16 @@ static bool htab_has_extra_elems(struct bpf_htab *htab)
 	return !htab_is_percpu(htab) && !htab_is_lru(htab) && !is_fd_htab(htab);
 }
 
+static void htab_free_internal_structs(struct bpf_htab *htab, struct htab_elem *elem)
+{
+	if (btf_record_has_field(htab->map.record, BPF_TIMER))
+		bpf_obj_free_timer(htab->map.record,
+				   htab_elem_value(elem, htab->map.key_size));
+	if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE))
+		bpf_obj_free_workqueue(htab->map.record,
+				       htab_elem_value(elem, htab->map.key_size));
+}
+
 static void htab_free_prealloced_timers_and_wq(struct bpf_htab *htab)
 {
 	u32 num_entries = htab->map.max_entries;
@@ -227,12 +237,7 @@ static void htab_free_prealloced_timers_and_wq(struct bpf_htab *htab)
 		struct htab_elem *elem;
 
 		elem = get_htab_elem(htab, i);
-		if (btf_record_has_field(htab->map.record, BPF_TIMER))
-			bpf_obj_free_timer(htab->map.record,
-					   htab_elem_value(elem, htab->map.key_size));
-		if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE))
-			bpf_obj_free_workqueue(htab->map.record,
-					       htab_elem_value(elem, htab->map.key_size));
+		htab_free_internal_structs(htab, elem);
 		cond_resched();
 	}
 }
@@ -1502,12 +1507,7 @@ static void htab_free_malloced_timers_and_wq(struct bpf_htab *htab)
 
 		hlist_nulls_for_each_entry(l, n, head, hash_node) {
 			/* We only free timer on uref dropping to zero */
-			if (btf_record_has_field(htab->map.record, BPF_TIMER))
-				bpf_obj_free_timer(htab->map.record,
-						   htab_elem_value(l, htab->map.key_size));
-			if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE))
-				bpf_obj_free_workqueue(htab->map.record,
-						       htab_elem_value(l, htab->map.key_size));
+			htab_free_internal_structs(htab, l);
 		}
 		cond_resched_rcu();
 	}