From patchwork Wed Jul 26 21:25:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pauli Virtanen X-Patchwork-Id: 13328580 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9488FC001DC for ; Wed, 26 Jul 2023 21:26:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231485AbjGZV0G (ORCPT ); Wed, 26 Jul 2023 17:26:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231345AbjGZV0D (ORCPT ); Wed, 26 Jul 2023 17:26:03 -0400 Received: from meesny.iki.fi (meesny.iki.fi [195.140.195.201]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2998326A8 for ; Wed, 26 Jul 2023 14:25:47 -0700 (PDT) Received: from monolith.lan (91-152-120-101.elisa-laajakaista.fi [91.152.120.101]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pav) by meesny.iki.fi (Postfix) with ESMTPSA id 4RB6Q161v0z107j; Thu, 27 Jul 2023 00:25:45 +0300 (EEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=meesny; t=1690406745; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2hPuiy3xlYhwpql/vmJpKc986dGEM1JauIIbxMsiXH8=; b=iNQSvc2B4ZbViTPjNdWYH0WPRfzD/dDo24qdIVZNFezRnZa4KxnfO2pXXELhEVvBR+4suN s6dwuxeL63kvs1C/yKeEcSmZm7cnd/jW3PhUzEmTWiPgqgy+wcGlheYxb1LuT60rwz2BmM Pu9nbOZ7drrGVqF7mJa2KLfPW5bzQHY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=meesny; t=1690406745; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2hPuiy3xlYhwpql/vmJpKc986dGEM1JauIIbxMsiXH8=; b=c5zXbYQ3tSt8uk1c0wJxqh/5OCbhpAa1TDJwFhYGWvc4zGy6N1VlpRr5Xye7viBpMpMffX 4Wv6QEjPiC3hu1NPqUK3rV73ZtBUeCOBFRmpuTiGEz7XDYW8iyA6PZ7H3dViM/12jqFzyK ybA73niXV0BpXazi9FZ1qbS9LhheoW0= ARC-Authentication-Results: i=1; ORIGINATING; auth=pass smtp.auth=pav smtp.mailfrom=pav@iki.fi ARC-Seal: i=1; s=meesny; d=iki.fi; t=1690406745; a=rsa-sha256; cv=none; b=Pazk0Y4BXQZLYzzMP0dmYy/EberXneDdcMVWF0t6mD0iGpCwNQNtw1/8zwYQo0F1MXvGfL IAKcsWuUTErJ+ScmcMRcuc36nXKJcBpMvWHj5JXhxOtd9bJ66lIPuQg3w//N2Ec7a6P5R9 7gOrP/9gUy0S7kInvSxz1Z+zBw4rFC4= From: Pauli Virtanen To: linux-bluetooth@vger.kernel.org Cc: Pauli Virtanen Subject: [PATCH RFC 3/6] Bluetooth: hci_sync: add hci_conn_sync_queue and hci_cmd_sync_dev_(un)lock Date: Thu, 27 Jul 2023 00:25:23 +0300 Message-ID: <15e7863c06bd87cd991ab963132fa9d12ef7e11a.1690399379.git.pav@iki.fi> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Operations on a given hci_conn in hci_sync are hard to write safely, because the conn might be deleted or modified unexpectedly either concurrently or when waiting for the events. Holding hci_dev_lock in the sync callbacks is also inconvenient since it has to be manually released before entering the event waits. Add convenience utilities to make things easier: Add hci_cmd_sync_dev_lock/unlock, for easier writing of hci_sync callbacks where hci_dev_lock should be held. The lock is however still released and reacquired around request waits. Callbacks using them can then assume that state changes protected by hci_dev_lock can only occur when waiting for events. (This is currently assumed in many of the callbacks.) Add hci_conn_sync_queue/submit, whose callback on entry holds hci_dev_lock and the hci_conn has not been deleted. If it was deleted while the sync command was queued, the destroy routine has err -ENODEV. Similarly, synchronous commands called in the callback fail with ENODEV if the conn was deleted during the wait. Signed-off-by: Pauli Virtanen --- include/net/bluetooth/hci_core.h | 7 ++++ include/net/bluetooth/hci_sync.h | 3 ++ net/bluetooth/hci_conn.c | 60 ++++++++++++++++++++++++++++++++ net/bluetooth/hci_sync.c | 31 +++++++++++++++++ 4 files changed, 101 insertions(+) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 34e4ad7c32e7..8e218300ef4e 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -519,6 +519,9 @@ struct hci_dev { struct work_struct cmd_sync_cancel_work; struct work_struct reenable_adv_work; + bool cmd_sync_locked; + struct hci_conn *cmd_sync_conn; + __u16 discov_timeout; struct delayed_work discov_off; @@ -1400,6 +1403,10 @@ void hci_conn_del(struct hci_conn *conn); void hci_conn_hash_flush(struct hci_dev *hdev); void hci_conn_check_pending(struct hci_dev *hdev); +void hci_conn_sync_set_conn(struct hci_dev *hdev, struct hci_conn *conn); +int hci_conn_sync_queue(struct hci_conn *conn, hci_cmd_sync_work_func_t func, + void *data, hci_cmd_sync_work_destroy_t destroy); + struct hci_chan *hci_chan_create(struct hci_conn *conn); void hci_chan_del(struct hci_chan *chan); void hci_chan_list_flush(struct hci_conn *conn); diff --git a/include/net/bluetooth/hci_sync.h b/include/net/bluetooth/hci_sync.h index b516a0f4a55b..a9a94950d523 100644 --- a/include/net/bluetooth/hci_sync.h +++ b/include/net/bluetooth/hci_sync.h @@ -46,6 +46,9 @@ int hci_cmd_sync_submit(struct hci_dev *hdev, hci_cmd_sync_work_func_t func, int hci_cmd_sync_queue(struct hci_dev *hdev, hci_cmd_sync_work_func_t func, void *data, hci_cmd_sync_work_destroy_t destroy); +void hci_cmd_sync_dev_lock(struct hci_dev *hdev); +void hci_cmd_sync_dev_unlock(struct hci_dev *hdev); + int hci_update_eir_sync(struct hci_dev *hdev); int hci_update_class_sync(struct hci_dev *hdev); diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index ee304618bf0a..208eb5eea451 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -2889,3 +2889,63 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason) return hci_cmd_sync_queue(hdev, abort_conn_sync, ERR_PTR(conn->handle), NULL); } + +struct hci_conn_sync_work_entry { + struct hci_conn *conn; + hci_cmd_sync_work_func_t func; + void *data; + hci_cmd_sync_work_destroy_t destroy; +}; + +static int hci_conn_sync_work_run(struct hci_dev *hdev, void *data) +{ + struct hci_conn_sync_work_entry *entry = data; + int err; + + hci_cmd_sync_dev_lock(hdev); + hdev->cmd_sync_conn = entry->conn; + + if (hci_conn_is_alive(hdev, entry->conn)) + err = entry->func(hdev, entry->data); + else + err = -ENODEV; + + hdev->cmd_sync_conn = NULL; + hci_cmd_sync_dev_unlock(hdev); + + return err; +} + +static void hci_conn_sync_work_destroy(struct hci_dev *hdev, void *data, + int err) +{ + struct hci_conn_sync_work_entry *entry = data; + + if (entry->destroy) + entry->destroy(hdev, entry->data, err); + hci_conn_put(entry->conn); + kfree(entry); +} + +int hci_conn_sync_queue(struct hci_conn *conn, hci_cmd_sync_work_func_t func, + void *data, hci_cmd_sync_work_destroy_t destroy) +{ + struct hci_conn_sync_work_entry *entry; + int err; + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + + entry->func = func; + entry->data = data; + entry->destroy = destroy; + entry->conn = hci_conn_get(conn); + + err = hci_cmd_sync_queue(conn->hdev, hci_conn_sync_work_run, entry, + hci_conn_sync_work_destroy); + if (err) + kfree(entry); + + return err; +} diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 3348a1b0e3f7..6a295a9e1f5d 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -164,10 +164,16 @@ struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen, if (err < 0) return ERR_PTR(err); + if (hdev->cmd_sync_locked) + hci_dev_unlock(hdev); + err = wait_event_interruptible_timeout(hdev->req_wait_q, hdev->req_status != HCI_REQ_PEND, timeout); + if (hdev->cmd_sync_locked) + hci_dev_lock(hdev); + if (err == -ERESTARTSYS) return ERR_PTR(-EINTR); @@ -185,6 +191,11 @@ struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen, break; } + if (hdev->cmd_sync_conn) { + if (!hci_conn_is_alive(hdev, hdev->cmd_sync_conn)) + err = -ENODEV; + } + hdev->req_status = 0; hdev->req_result = 0; skb = hdev->req_skb; @@ -740,6 +751,26 @@ int hci_cmd_sync_queue(struct hci_dev *hdev, hci_cmd_sync_work_func_t func, } EXPORT_SYMBOL(hci_cmd_sync_queue); +void hci_cmd_sync_dev_lock(struct hci_dev *hdev) +{ + lockdep_assert_held(&hdev->req_lock); + + hci_dev_lock(hdev); + + WARN_ON_ONCE(hdev->cmd_sync_locked); + hdev->cmd_sync_locked = true; +} + +void hci_cmd_sync_dev_unlock(struct hci_dev *hdev) +{ + lockdep_assert_held(&hdev->req_lock); + + WARN_ON_ONCE(!hdev->cmd_sync_locked); + hdev->cmd_sync_locked = false; + + hci_dev_unlock(hdev); +} + int hci_update_eir_sync(struct hci_dev *hdev) { struct hci_cp_write_eir cp;