bpf: allow struct bpf_wq to be embedded in arraymaps and hashmaps

Currently bpf_wq_cancel_and_free() is just a placeholder as there is
no memory allocation for bpf_wq just yet.

Again, duplication of the bpf_timer approach

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-9-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 43 insertions, 12 deletions

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index c3e79a0b9361..0179183c543a 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -240,6 +240,26 @@ static void htab_free_prealloced_timers(struct bpf_htab *htab)
 	}
 }
 
+static void htab_free_prealloced_wq(struct bpf_htab *htab)
+{
+	u32 num_entries = htab->map.max_entries;
+	int i;
+
+	if (!btf_record_has_field(htab->map.record, BPF_WORKQUEUE))
+		return;
+	if (htab_has_extra_elems(htab))
+		num_entries += num_possible_cpus();
+
+	for (i = 0; i < num_entries; i++) {
+		struct htab_elem *elem;
+
+		elem = get_htab_elem(htab, i);
+		bpf_obj_free_workqueue(htab->map.record,
+				       elem->key + round_up(htab->map.key_size, 8));
+		cond_resched();
+	}
+}
+
 static void htab_free_prealloced_fields(struct bpf_htab *htab)
 {
 	u32 num_entries = htab->map.max_entries;
@@ -1495,7 +1515,7 @@ static void delete_all_elements(struct bpf_htab *htab)
 	migrate_enable();
 }
 
-static void htab_free_malloced_timers(struct bpf_htab *htab)
+static void htab_free_malloced_timers_or_wq(struct bpf_htab *htab, bool is_timer)
 {
 	int i;
 
@@ -1507,24 +1527,35 @@ static void htab_free_malloced_timers(struct bpf_htab *htab)
 
 		hlist_nulls_for_each_entry(l, n, head, hash_node) {
 			/* We only free timer on uref dropping to zero */
-			bpf_obj_free_timer(htab->map.record, l->key + round_up(htab->map.key_size, 8));
+			if (is_timer)
+				bpf_obj_free_timer(htab->map.record,
+						   l->key + round_up(htab->map.key_size, 8));
+			else
+				bpf_obj_free_workqueue(htab->map.record,
+						       l->key + round_up(htab->map.key_size, 8));
 		}
 		cond_resched_rcu();
 	}
 	rcu_read_unlock();
 }
 
-static void htab_map_free_timers(struct bpf_map *map)
+static void htab_map_free_timers_and_wq(struct bpf_map *map)
 {
 	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
 
-	/* We only free timer on uref dropping to zero */
-	if (!btf_record_has_field(htab->map.record, BPF_TIMER))
-		return;
-	if (!htab_is_prealloc(htab))
-		htab_free_malloced_timers(htab);
-	else
-		htab_free_prealloced_timers(htab);
+	/* We only free timer and workqueue on uref dropping to zero */
+	if (btf_record_has_field(htab->map.record, BPF_TIMER)) {
+		if (!htab_is_prealloc(htab))
+			htab_free_malloced_timers_or_wq(htab, true);
+		else
+			htab_free_prealloced_timers(htab);
+	}
+	if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE)) {
+		if (!htab_is_prealloc(htab))
+			htab_free_malloced_timers_or_wq(htab, false);
+		else
+			htab_free_prealloced_wq(htab);
+	}
 }
 
 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
@@ -2260,7 +2291,7 @@ const struct bpf_map_ops htab_map_ops = {
 	.map_alloc = htab_map_alloc,
 	.map_free = htab_map_free,
 	.map_get_next_key = htab_map_get_next_key,
-	.map_release_uref = htab_map_free_timers,
+	.map_release_uref = htab_map_free_timers_and_wq,
 	.map_lookup_elem = htab_map_lookup_elem,
 	.map_lookup_and_delete_elem = htab_map_lookup_and_delete_elem,
 	.map_update_elem = htab_map_update_elem,
@@ -2281,7 +2312,7 @@ const struct bpf_map_ops htab_lru_map_ops = {
 	.map_alloc = htab_map_alloc,
 	.map_free = htab_map_free,
 	.map_get_next_key = htab_map_get_next_key,
-	.map_release_uref = htab_map_free_timers,
+	.map_release_uref = htab_map_free_timers_and_wq,
 	.map_lookup_elem = htab_lru_map_lookup_elem,
 	.map_lookup_and_delete_elem = htab_lru_map_lookup_and_delete_elem,
 	.map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,