One more thing I missed yesterday:
On Mon, 25 Jan 2021, Guennadi Liakhovetski wrote:
On Sun, 24 Jan 2021, Anton Yakovlev wrote:
Introduce the operators required for the operation of substreams.
Signed-off-by: Anton Yakovlev <anton.yakovlev@xxxxxxxxxxxxxxx>
---
sound/virtio/Makefile | 3 +-
sound/virtio/virtio_pcm.c | 5 +-
sound/virtio/virtio_pcm.h | 2 +
sound/virtio/virtio_pcm_ops.c | 513 ++++++++++++++++++++++++++++++++++
4 files changed, 521 insertions(+), 2 deletions(-)
create mode 100644 sound/virtio/virtio_pcm_ops.c
[snip]
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
new file mode 100644
index 000000000000..19882777fcd6
--- /dev/null
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -0,0 +1,513 @@
[snip]
+/**
+ * virtsnd_pcm_release() - Release the PCM substream on the device side.
+ * @substream: VirtIO substream.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+static inline bool virtsnd_pcm_released(struct virtio_pcm_substream
*substream)
+{
+ /*
+ * The spec states that upon receipt of the RELEASE command "the
device
+ * MUST complete all pending I/O messages for the specified stream
ID".
+ * Thus, we consider the absence of I/O messages in the queue as an
+ * indication that the substream has been released.
+ */
+ return atomic_read(&substream->msg_count) == 0;
Also here having it atomic doesn't really seem to help. This just means, that
at some point of time it was == 0.
+}
+
+static int virtsnd_pcm_release(struct virtio_pcm_substream *substream)
kernel-doc missing
+{
+ struct virtio_snd *snd = substream->snd;
+ struct virtio_snd_msg *msg;
+ unsigned int js = msecs_to_jiffies(msg_timeout_ms);
+ int rc;
+
+ msg = virtsnd_pcm_ctl_msg_alloc(substream, VIRTIO_SND_R_PCM_RELEASE,
+ GFP_KERNEL);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ rc = virtsnd_ctl_msg_send_sync(snd, msg);
+ if (rc)
+ return rc;
+
+ return wait_event_interruptible_timeout(substream->msg_empty,
+ virtsnd_pcm_released(substream),
+ js);
wait_event_interruptible_timeout() will return a positive number in
success cases, 0 means a timeout and condition still false. Whereas when
you call this function you interpret 0 as success and you expect any != 0
to be a negative error. Wondering how this worked during your tests?
Thanks
Guennadi
