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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [PATCH] Bluetooth: hci_sync: Only allow hci_cmd_sync_queue if running
Date:   Fri, 21 Apr 2023 11:47:16 -0700
Message-Id: <20230421184716.2846319-1-luiz.dentz@gmail.com>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This makes sure hci_cmd_sync_queue only queue new work if HCI_RUNNING
has been set otherwise there is a risk of commands being sent while
turning off.

Because hci_cmd_sync_queue can no longer queue work while HCI_RUNNING is
not set it cannot be used to power on adapters so instead
hci_cmd_sync_submit is introduced which bypass the HCI_RUNNING check, so
it behaves like the old implementation.

Link: https://lore.kernel.org/all/CAB4PzUpDMvdc8j2MdeSAy1KkAE-D3woprCwAdYWeOc-3v3c9Sw@mail.gmail.com/
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci_sync.h |  2 ++
 net/bluetooth/hci_sync.c         | 25 +++++++++++++++++++++++--
 net/bluetooth/mgmt.c             | 12 ++++++++----
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/include/net/bluetooth/hci_sync.h b/include/net/bluetooth/hci_sync.h
index f61b249787fc..2495be4d8b82 100644
--- a/include/net/bluetooth/hci_sync.h
+++ b/include/net/bluetooth/hci_sync.h
@@ -41,6 +41,8 @@ void hci_cmd_sync_clear(struct hci_dev *hdev);
 void hci_cmd_sync_cancel(struct hci_dev *hdev, int err);
 void __hci_cmd_sync_cancel(struct hci_dev *hdev, int err);
 
+int hci_cmd_sync_submit(struct hci_dev *hdev, hci_cmd_sync_work_func_t func,
+			void *data, hci_cmd_sync_work_destroy_t destroy);
 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);
 
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 771aaa808967..647a8ce54062 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -684,8 +684,12 @@ void hci_cmd_sync_cancel(struct hci_dev *hdev, int err)
 }
 EXPORT_SYMBOL(hci_cmd_sync_cancel);
 
-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)
+/* Submit HCI command to be run in as cmd_sync_work:
+ *
+ * - hdev must _not_ be unregistered
+ */
+int hci_cmd_sync_submit(struct hci_dev *hdev, hci_cmd_sync_work_func_t func,
+			void *data, hci_cmd_sync_work_destroy_t destroy)
 {
 	struct hci_cmd_sync_work_entry *entry;
 
@@ -708,6 +712,23 @@ int hci_cmd_sync_queue(struct hci_dev *hdev, hci_cmd_sync_work_func_t func,
 
 	return 0;
 }
+EXPORT_SYMBOL(hci_cmd_sync_submit);
+
+/* Queue HCI command:
+ *
+ * - hdev must be running
+ */
+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)
+{
+	/* Only queue command if hdev is running which means it had been opened
+	 * and is either on init phase or is already up.
+	 */
+	if (!test_bit(HCI_RUNNING, &hdev->flags))
+		return -ENETDOWN;
+
+	return hci_cmd_sync_submit(hdev, func, data, destroy);
+}
 EXPORT_SYMBOL(hci_cmd_sync_queue);
 
 int hci_update_eir_sync(struct hci_dev *hdev)
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 13c745876b39..f7b2d0971f24 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -1400,11 +1400,15 @@ static int set_powered(struct sock *sk, struct hci_dev *hdev, void *data,
 	}
 
 	/* Cancel potentially blocking sync operation before power off */
-	if (cp->val == 0x00)
+	if (cp->val == 0x00) {
 		__hci_cmd_sync_cancel(hdev, -EHOSTDOWN);
-
-	err = hci_cmd_sync_queue(hdev, set_powered_sync, cmd,
-				 mgmt_set_powered_complete);
+		err = hci_cmd_sync_queue(hdev, set_powered_sync, cmd,
+					 mgmt_set_powered_complete);
+	} else {
+		/* Use hci_cmd_sync_submit since hdev might not be running */
+		err = hci_cmd_sync_submit(hdev, set_powered_sync, cmd,
+					  mgmt_set_powered_complete);
+	}
 
 	if (err < 0)
 		mgmt_pending_remove(cmd);
-- 
2.39.2