Bluetooth: btintel_pcie: Fix a potential race condition

On HCI_OP_RESET command, firmware raises alive interrupt. Driver needs
to wait for this before sending other command. This patch fixes the potential
miss of alive interrupt due to which HCI_OP_RESET can timeout.

Expected flow:
If tx command is HCI_OP_RESET,
  1. set data->gp0_received = false
  2. send HCI_OP_RESET
  3. wait for alive interrupt

Actual flow having potential race:
If tx command is HCI_OP_RESET,
 1. send HCI_OP_RESET
   1a. Firmware raises alive interrupt here and in ISR
       data->gp0_received  is set to true
 2. set data->gp0_received = false
 3. wait for alive interrupt

Signed-off-by: Kiran K <[email protected]>
Fixes: 05c200c ("Bluetooth: btintel_pcie: Add handshake between driver and firmware")
Reported-by: Bjorn Helgaas <[email protected]>
Closes: https://patchwork.kernel.org/project/bluetooth/patch/[email protected]/
Signed-off-by: Luiz Augusto von Dentz <[email protected]>

Author: kirankrishnappa-intel

drivers/bluetooth/btintel_pcie.c

@@ -1320,6 +1320,10 @@ static int btintel_pcie_send_frame(struct hci_dev *hdev,
 			if (opcode == 0xfc01)
 				btintel_pcie_inject_cmd_complete(hdev, opcode);
 		}
+		/* Firmware raises alive interrupt on HCI_OP_RESET */
+		if (opcode == HCI_OP_RESET)
+			data->gp0_received = false;
+
 		hdev->stat.cmd_tx++;
 		break;
 	case HCI_ACLDATA_PKT:
@@ -1357,7 +1361,6 @@ static int btintel_pcie_send_frame(struct hci_dev *hdev,
 			   opcode, btintel_pcie_alivectxt_state2str(old_ctxt),
 			   btintel_pcie_alivectxt_state2str(data->alive_intr_ctxt));
 		if (opcode == HCI_OP_RESET) {
-			data->gp0_received = false;
 			ret = wait_event_timeout(data->gp0_wait_q,
 						 data->gp0_received,
 						 msecs_to_jiffies(BTINTEL_DEFAULT_INTR_TIMEOUT_MS));