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(syn-107-146-107-067.res.spectrum.com. [107.146.107.67]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-856557908a3sm358193241.30.2024.11.07.10.34.59 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Nov 2024 10:35:00 -0800 (PST) From: Luiz Augusto von Dentz To: linux-bluetooth@vger.kernel.org Subject: [PATCH v1 2/2] Bluetooth: ISO: Use kref to track lifetime of iso_conn Date: Thu, 7 Nov 2024 13:34:55 -0500 Message-ID: <20241107183455.129897-2-luiz.dentz@gmail.com> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241107183455.129897-1-luiz.dentz@gmail.com> References: <20241107183455.129897-1-luiz.dentz@gmail.com> Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Luiz Augusto von Dentz This make use of kref to keep track of reference of iso_conn which allows better tracking of its lifetime with usage of things like kref_get_unless_zero in a similar way as used in l2cap_chan. In addition to it remove call to iso_sock_set_timer on iso_sock_disconn since at that point it is useless to set a timer as the sk will be freed there is nothing to be done in iso_sock_timeout. Fixes: ccf74f2390d6 ("Bluetooth: Add BTPROTO_ISO socket type") Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/iso.c | 88 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 71 insertions(+), 17 deletions(-) diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c index 9e119da43147..24e78ada9ad2 100644 --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -35,6 +35,7 @@ struct iso_conn { struct sk_buff *rx_skb; __u32 rx_len; __u16 tx_sn; + struct kref ref; }; #define iso_conn_lock(c) spin_lock(&(c)->lock) @@ -93,6 +94,49 @@ static struct sock *iso_get_sock(bdaddr_t *src, bdaddr_t *dst, #define ISO_CONN_TIMEOUT (HZ * 40) #define ISO_DISCONN_TIMEOUT (HZ * 2) +static void iso_conn_free(struct kref *ref) +{ + struct iso_conn *conn = container_of(ref, struct iso_conn, ref); + + BT_DBG("conn %p", conn); + + if (conn->sk) + iso_pi(conn->sk)->conn = NULL; + + if (conn->hcon) { + conn->hcon->iso_data = NULL; + hci_conn_drop(conn->hcon); + } + + /* Ensure no more work items will run since hci_conn has been dropped */ + disable_delayed_work_sync(&conn->timeout_work); + + kfree(conn); +} + +static void iso_conn_put(struct iso_conn *conn) +{ + if (!conn) + return; + + BT_DBG("conn %p refcnt %d", conn, kref_read(&conn->ref)); + + kref_put(&conn->ref, iso_conn_free); +} + +static struct iso_conn *iso_conn_hold_unless_zero(struct iso_conn *conn) +{ + if (!conn) + return NULL; + + BT_DBG("conn %p refcnt %u", conn, kref_read(&conn->ref)); + + if (!kref_get_unless_zero(&conn->ref)) + return NULL; + + return conn; +} + static struct sock *iso_sock_hold(struct iso_conn *conn) { if (!conn || !bt_sock_linked(&iso_sk_list, conn->sk)) @@ -109,9 +153,14 @@ static void iso_sock_timeout(struct work_struct *work) timeout_work.work); struct sock *sk; + conn = iso_conn_hold_unless_zero(conn); + if (!conn) + return; + iso_conn_lock(conn); sk = iso_sock_hold(conn); iso_conn_unlock(conn); + iso_conn_put(conn); if (!sk) return; @@ -149,9 +198,14 @@ static struct iso_conn *iso_conn_add(struct hci_conn *hcon) { struct iso_conn *conn = hcon->iso_data; + conn = iso_conn_hold_unless_zero(conn); if (conn) { - if (!conn->hcon) + if (!conn->hcon) { + iso_conn_lock(conn); conn->hcon = hcon; + iso_conn_unlock(conn); + } + iso_conn_put(conn); return conn; } @@ -159,6 +213,7 @@ static struct iso_conn *iso_conn_add(struct hci_conn *hcon) if (!conn) return NULL; + kref_init(&conn->ref); spin_lock_init(&conn->lock); INIT_DELAYED_WORK(&conn->timeout_work, iso_sock_timeout); @@ -178,17 +233,15 @@ static void iso_chan_del(struct sock *sk, int err) struct sock *parent; conn = iso_pi(sk)->conn; + iso_pi(sk)->conn = NULL; BT_DBG("sk %p, conn %p, err %d", sk, conn, err); if (conn) { iso_conn_lock(conn); conn->sk = NULL; - iso_pi(sk)->conn = NULL; iso_conn_unlock(conn); - - if (conn->hcon) - hci_conn_drop(conn->hcon); + iso_conn_put(conn); } sk->sk_state = BT_CLOSED; @@ -210,6 +263,7 @@ static void iso_conn_del(struct hci_conn *hcon, int err) struct iso_conn *conn = hcon->iso_data; struct sock *sk; + conn = iso_conn_hold_unless_zero(conn); if (!conn) return; @@ -219,20 +273,18 @@ static void iso_conn_del(struct hci_conn *hcon, int err) iso_conn_lock(conn); sk = iso_sock_hold(conn); iso_conn_unlock(conn); + iso_conn_put(conn); - if (sk) { - lock_sock(sk); - iso_sock_clear_timer(sk); - iso_chan_del(sk, err); - release_sock(sk); - sock_put(sk); + if (!sk) { + iso_conn_put(conn); + return; } - /* Ensure no more work items will run before freeing conn. */ - cancel_delayed_work_sync(&conn->timeout_work); - - hcon->iso_data = NULL; - kfree(conn); + lock_sock(sk); + iso_sock_clear_timer(sk); + iso_chan_del(sk, err); + release_sock(sk); + sock_put(sk); } static int __iso_chan_add(struct iso_conn *conn, struct sock *sk, @@ -652,6 +704,8 @@ static void iso_sock_destruct(struct sock *sk) { BT_DBG("sk %p", sk); + iso_conn_put(iso_pi(sk)->conn); + skb_queue_purge(&sk->sk_receive_queue); skb_queue_purge(&sk->sk_write_queue); } @@ -711,6 +765,7 @@ static void iso_sock_disconn(struct sock *sk) */ if (bis_sk) { hcon->state = BT_OPEN; + hcon->iso_data = NULL; iso_pi(sk)->conn->hcon = NULL; iso_sock_clear_timer(sk); iso_chan_del(sk, bt_to_errno(hcon->abort_reason)); @@ -720,7 +775,6 @@ static void iso_sock_disconn(struct sock *sk) } sk->sk_state = BT_DISCONN; - iso_sock_set_timer(sk, ISO_DISCONN_TIMEOUT); iso_conn_lock(iso_pi(sk)->conn); hci_conn_drop(iso_pi(sk)->conn->hcon); iso_pi(sk)->conn->hcon = NULL;