bpf, sockmap: Fix bug that strp_done cannot be called

strp_done is only called when psock->progs.stream_parser is not NULL,
but stream_parser was set to NULL by sk_psock_stop_strp(), called
by sk_psock_drop() earlier. So, strp_done can never be called.

Introduce SK_PSOCK_RX_ENABLED to mark whether there is strp on psock.
Change the condition for calling strp_done from judging whether
stream_parser is set to judging whether this flag is set. This flag is
only set once when strp_init() succeeds, and will never be cleared later.

Fixes: c0d95d3 ("bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmap")
Signed-off-by: Xu Kuohai <[email protected]>
Reviewed-by: John Fastabend <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin KaFai Lau <[email protected]>

Author: Xu Kuohai

include/linux/skmsg.h

@@ -62,6 +62,7 @@ struct sk_psock_progs {
 
 enum sk_psock_state_bits {
 	SK_PSOCK_TX_ENABLED,
+	SK_PSOCK_RX_STRP_ENABLED,
 };
 
 struct sk_psock_link {

net/core/skmsg.c

@@ -1120,13 +1120,19 @@ static void sk_psock_strp_data_ready(struct sock *sk)
 
 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 {
+	int ret;
+
 	static const struct strp_callbacks cb = {
 		.rcv_msg	= sk_psock_strp_read,
 		.read_sock_done	= sk_psock_strp_read_done,
 		.parse_msg	= sk_psock_strp_parse,
 	};
 
-	return strp_init(&psock->strp, sk, &cb);
+	ret = strp_init(&psock->strp, sk, &cb);
+	if (!ret)
+		sk_psock_set_state(psock, SK_PSOCK_RX_STRP_ENABLED);
+
+	return ret;
 }
 
 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
@@ -1154,7 +1160,7 @@ void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 static void sk_psock_done_strp(struct sk_psock *psock)
 {
 	/* Parser has been stopped */
-	if (psock->progs.stream_parser)
+	if (sk_psock_test_state(psock, SK_PSOCK_RX_STRP_ENABLED))
 		strp_done(&psock->strp);
 }
 #else