[PATCH 6.1 200/451] Bluetooth: hci_conn: Consolidate code for aborting connections

Sasha Levin
2024-03-24T23:15:24Z

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Upstream commit a13f316e90fdb1fb6df6582e845aa9b3270f3581 ]

This consolidates code for aborting connections using
hci_cmd_sync_queue so it is synchronized with other threads, but
because of the fact that some commands may block the cmd_sync_queue
while waiting specific events this attempt to cancel those requests by
using hci_cmd_sync_cancel.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Stable-dep-of: 2615fd9a7c25 ("Bluetooth: hci_sync: Fix overwriting request callback")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/bluetooth/hci_core.h | 2 +-
net/bluetooth/hci_conn.c | 154 ++++++-------------------------
net/bluetooth/hci_sync.c | 23 +++--
net/bluetooth/mgmt.c | 15 +--
4 files changed, 47 insertions(+), 147 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 09c978f3d95dc..2538f3b96623b 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -739,6 +739,7 @@ struct hci_conn {
unsigned long flags;

enum conn_reasons conn_reason;
+ __u8 abort_reason;

__u32 clock;
__u16 clock_accuracy;
@@ -758,7 +759,6 @@ struct hci_conn {
struct delayed_work auto_accept_work;
struct delayed_work idle_work;
struct delayed_work le_conn_timeout;
- struct work_struct le_scan_cleanup;

struct device dev;
struct dentry *debugfs;
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 12d36875358b9..f752a9f9bb9c7 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -175,57 +175,6 @@ static void hci_conn_cleanup(struct hci_conn *conn)
hci_dev_put(hdev);
}

-static void le_scan_cleanup(struct work_struct *work)
-{
- struct hci_conn *conn = container_of(work, struct hci_conn,
- le_scan_cleanup);
- struct hci_dev *hdev = conn->hdev;
- struct hci_conn *c = NULL;
-
- BT_DBG("%s hcon %p", hdev->name, conn);
-
- hci_dev_lock(hdev);
-
- /* Check that the hci_conn is still around */
- rcu_read_lock();
- list_for_each_entry_rcu(c, &hdev->conn_hash.list, list) {
- if (c == conn)
- break;
- }
- rcu_read_unlock();
-
- if (c == conn) {
- hci_connect_le_scan_cleanup(conn, 0x00);
- hci_conn_cleanup(conn);
- }
-
- hci_dev_unlock(hdev);
- hci_dev_put(hdev);
- hci_conn_put(conn);
-}
-
-static void hci_connect_le_scan_remove(struct hci_conn *conn)
-{
- BT_DBG("%s hcon %p", conn->hdev->name, conn);
-
- /* We can't call hci_conn_del/hci_conn_cleanup here since that
- * could deadlock with another hci_conn_del() call that's holding
- * hci_dev_lock and doing cancel_delayed_work_sync(&conn->disc_work).
- * Instead, grab temporary extra references to the hci_dev and
- * hci_conn and perform the necessary cleanup in a separate work
- * callback.
- */
-
- hci_dev_hold(conn->hdev);
- hci_conn_get(conn);
-
- /* Even though we hold a reference to the hdev, many other
- * things might get cleaned up meanwhile, including the hdev's
- * own workqueue, so we can't use that for scheduling.
- */
- schedule_work(&conn->le_scan_cleanup);
-}
-
static void hci_acl_create_connection(struct hci_conn *conn)
{
struct hci_dev *hdev = conn->hdev;
@@ -672,13 +621,6 @@ static void hci_conn_timeout(struct work_struct *work)
if (refcnt > 0)
return;

- /* LE connections in scanning state need special handling */
- if (conn->state == BT_CONNECT && conn->type == LE_LINK &&
- test_bit(HCI_CONN_SCANNING, &conn->flags)) {
- hci_connect_le_scan_remove(conn);
- return;
- }
-
hci_abort_conn(conn, hci_proto_disconn_ind(conn));
}

@@ -1050,7 +992,6 @@ struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
INIT_DELAYED_WORK(&conn->auto_accept_work, hci_conn_auto_accept);
INIT_DELAYED_WORK(&conn->idle_work, hci_conn_idle);
INIT_DELAYED_WORK(&conn->le_conn_timeout, le_conn_timeout);
- INIT_WORK(&conn->le_scan_cleanup, le_scan_cleanup);

atomic_set(&conn->refcnt, 0);

@@ -2837,81 +2778,46 @@ u32 hci_conn_get_phy(struct hci_conn *conn)
return phys;
}

-int hci_abort_conn(struct hci_conn *conn, u8 reason)
+static int abort_conn_sync(struct hci_dev *hdev, void *data)
{
- int r = 0;
+ struct hci_conn *conn;
+ u16 handle = PTR_ERR(data);

- if (test_and_set_bit(HCI_CONN_CANCEL, &conn->flags))
+ conn = hci_conn_hash_lookup_handle(hdev, handle);
+ if (!conn)
return 0;

- switch (conn->state) {
- case BT_CONNECTED:
- case BT_CONFIG:
- if (conn->type == AMP_LINK) {
- struct hci_cp_disconn_phy_link cp;
+ return hci_abort_conn_sync(hdev, conn, conn->abort_reason);
+}

- cp.phy_handle = HCI_PHY_HANDLE(conn->handle);
- cp.reason = reason;
- r = hci_send_cmd(conn->hdev, HCI_OP_DISCONN_PHY_LINK,
- sizeof(cp), &cp);
- } else {
- struct hci_cp_disconnect dc;
+int hci_abort_conn(struct hci_conn *conn, u8 reason)
+{
+ struct hci_dev *hdev = conn->hdev;

- dc.handle = cpu_to_le16(conn->handle);
- dc.reason = reason;
- r = hci_send_cmd(conn->hdev, HCI_OP_DISCONNECT,
- sizeof(dc), &dc);
- }
+ /* If abort_reason has already been set it means the connection is
+ * already being aborted so don't attempt to overwrite it.
+ */
+ if (conn->abort_reason)
+ return 0;

- conn->state = BT_DISCONN;
+ bt_dev_dbg(hdev, "handle 0x%2.2x reason 0x%2.2x", conn->handle, reason);

- break;
- case BT_CONNECT:
- if (conn->type == LE_LINK) {
- if (test_bit(HCI_CONN_SCANNING, &conn->flags))
- break;
- r = hci_send_cmd(conn->hdev,
- HCI_OP_LE_CREATE_CONN_CANCEL, 0, NULL);
- } else if (conn->type == ACL_LINK) {
- if (conn->hdev->hci_ver < BLUETOOTH_VER_1_2)
- break;
- r = hci_send_cmd(conn->hdev,
- HCI_OP_CREATE_CONN_CANCEL,
- 6, &conn->dst);
- }
- break;
- case BT_CONNECT2:
- if (conn->type == ACL_LINK) {
- struct hci_cp_reject_conn_req rej;
-
- bacpy(&rej.bdaddr, &conn->dst);
- rej.reason = reason;
-
- r = hci_send_cmd(conn->hdev,
- HCI_OP_REJECT_CONN_REQ,
- sizeof(rej), &rej);
- } else if (conn->type == SCO_LINK || conn->type == ESCO_LINK) {
- struct hci_cp_reject_sync_conn_req rej;
-
- bacpy(&rej.bdaddr, &conn->dst);
-
- /* SCO rejection has its own limited set of
- * allowed error values (0x0D-0x0F) which isn't
- * compatible with most values passed to this
- * function. To be safe hard-code one of the
- * values that's suitable for SCO.
- */
- rej.reason = HCI_ERROR_REJ_LIMITED_RESOURCES;
+ conn->abort_reason = reason;

- r = hci_send_cmd(conn->hdev,
- HCI_OP_REJECT_SYNC_CONN_REQ,
- sizeof(rej), &rej);
+ /* If the connection is pending check the command opcode since that
+ * might be blocking on hci_cmd_sync_work while waiting its respective
+ * event so we need to hci_cmd_sync_cancel to cancel it.
+ */
+ if (conn->state == BT_CONNECT && hdev->req_status == HCI_REQ_PEND) {
+ switch (hci_skb_event(hdev->sent_cmd)) {
+ case HCI_EV_LE_CONN_COMPLETE:
+ case HCI_EV_LE_ENHANCED_CONN_COMPLETE:
+ case HCI_EVT_LE_CIS_ESTABLISHED:
+ hci_cmd_sync_cancel(hdev, -ECANCELED);
+ break;
}
- break;
- default:
- conn->state = BT_CLOSED;
- break;
}

- return r;
+ return hci_cmd_sync_queue(hdev, abort_conn_sync, ERR_PTR(conn->handle),
+ NULL);
}
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 31dd064d77a42..c03729c10fdd6 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -5230,22 +5230,27 @@ static int hci_disconnect_sync(struct hci_dev *hdev, struct hci_conn *conn,
}

static int hci_le_connect_cancel_sync(struct hci_dev *hdev,
- struct hci_conn *conn)
+ struct hci_conn *conn, u8 reason)
{
+ /* Return reason if scanning since the connection shall probably be
+ * cleanup directly.
+ */
if (test_bit(HCI_CONN_SCANNING, &conn->flags))
- return 0;
+ return reason;

- if (test_and_set_bit(HCI_CONN_CANCEL, &conn->flags))
+ if (conn->role == HCI_ROLE_SLAVE ||
+ test_and_set_bit(HCI_CONN_CANCEL, &conn->flags))
return 0;

return __hci_cmd_sync_status(hdev, HCI_OP_LE_CREATE_CONN_CANCEL,
0, NULL, HCI_CMD_TIMEOUT);
}

-static int hci_connect_cancel_sync(struct hci_dev *hdev, struct hci_conn *conn)
+static int hci_connect_cancel_sync(struct hci_dev *hdev, struct hci_conn *conn,
+ u8 reason)
{
if (conn->type == LE_LINK)
- return hci_le_connect_cancel_sync(hdev, conn);
+ return hci_le_connect_cancel_sync(hdev, conn, reason);

if (hdev->hci_ver < BLUETOOTH_VER_1_2)
return 0;
@@ -5298,9 +5303,11 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason)
case BT_CONFIG:
return hci_disconnect_sync(hdev, conn, reason);
case BT_CONNECT:
- err = hci_connect_cancel_sync(hdev, conn);
+ err = hci_connect_cancel_sync(hdev, conn, reason);
/* Cleanup hci_conn object if it cannot be cancelled as it
- * likelly means the controller and host stack are out of sync.
+ * likelly means the controller and host stack are out of sync
+ * or in case of LE it was still scanning so it can be cleanup
+ * safely.
*/
if (err) {
hci_dev_lock(hdev);
@@ -6215,7 +6222,7 @@ int hci_le_create_conn_sync(struct hci_dev *hdev, struct hci_conn *conn)

done:
if (err == -ETIMEDOUT)
- hci_le_connect_cancel_sync(hdev, conn);
+ hci_le_connect_cancel_sync(hdev, conn, 0x00);

/* Re-enable advertising after the connection attempt is finished. */
hci_resume_advertising_sync(hdev);
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 732b6cf45fbe4..fbd859e2d13ca 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -3583,18 +3583,6 @@ static int pair_device(struct sock *sk, struct hci_dev *hdev, void *data,
return err;
}

-static int abort_conn_sync(struct hci_dev *hdev, void *data)
-{
- struct hci_conn *conn;
- u16 handle = PTR_ERR(data);
-
- conn = hci_conn_hash_lookup_handle(hdev, handle);
- if (!conn)
- return 0;
-
- return hci_abort_conn_sync(hdev, conn, HCI_ERROR_REMOTE_USER_TERM);
-}
-
static int cancel_pair_device(struct sock *sk, struct hci_dev *hdev, void *data,
u16 len)
{
@@ -3645,8 +3633,7 @@ static int cancel_pair_device(struct sock *sk, struct hci_dev *hdev, void *data,
le_addr_type(addr->type));

if (conn->conn_reason == CONN_REASON_PAIR_DEVICE)
- hci_cmd_sync_queue(hdev, abort_conn_sync, ERR_PTR(conn->handle),
- NULL);
+ hci_abort_conn(conn, HCI_ERROR_REMOTE_USER_TERM);

unlock:
hci_dev_unlock(hdev);
--
2.43.0