[v17,34/51] ALSA: usb-audio: Do not allow USB offload path if PCM device is in use

Commit Message

Wesley Cheng Feb. 17, 2024, 12:10 a.m. UTC

Add proper checks and updates to the USB substream once receiving a USB QMI
stream enable request.  If the substream is already in use from the non
offload path, reject the stream enable request.  In addition, update the
USB substream opened parameter when enabling the offload path, so the
non offload path can be blocked.

Signed-off-by: Wesley Cheng <[e-mail]>
---
 sound/usb/qcom/qc_audio_offload.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

Patch

diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
index 3b7780cb288a..db68c6c605eb 100644
--- a/sound/usb/qcom/qc_audio_offload.c
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -1460,12 +1460,17 @@  static void handle_uaudio_stream_req(struct qmi_handle *handle,
 		goto response;
 	}
 
+	mutex_lock(&chip->mutex);
 	if (req_msg->enable) {
-		if (info_idx < 0 || chip->system_suspend) {
+		if (info_idx < 0 || chip->system_suspend || subs->opened) {
 			ret = -EBUSY;
+			mutex_unlock(&chip->mutex);
+
 			goto response;
 		}
+		subs->opened = 1;
 	}
+	mutex_unlock(&chip->mutex);
 
 	if (req_msg->service_interval_valid) {
 		ret = get_data_interval_from_si(subs,
@@ -1487,6 +1492,11 @@  static void handle_uaudio_stream_req(struct qmi_handle *handle,
 		if (!ret)
 			ret = prepare_qmi_response(subs, req_msg, &resp,
 					info_idx);
+		if (ret < 0) {
+			mutex_lock(&chip->mutex);
+			subs->opened = 0;
+			mutex_unlock(&chip->mutex);
+		}
 	} else {
 		info = &uadev[pcm_card_num].info[info_idx];
 		if (info->data_ep_pipe) {
@@ -1510,6 +1520,9 @@  static void handle_uaudio_stream_req(struct qmi_handle *handle,
 		}
 
 		disable_audio_stream(subs);
+		mutex_lock(&chip->mutex);
+		subs->opened = 0;
+		mutex_unlock(&chip->mutex);
 	}
 
 response: