On 25.02.2021 11:38, Takashi Iwai wrote:
On Mon, 22 Feb 2021 16:34:37 +0100, Anton Yakovlev wrote:
+static int virtsnd_find_vqs(struct virtio_snd *snd) +{
struct virtio_device *vdev = snd->vdev;vq_callback_t *callbacks[VIRTIO_SND_VQ_MAX] = {[VIRTIO_SND_VQ_EVENT] = virtsnd_event_notify_cb};const char *names[VIRTIO_SND_VQ_MAX] = {Shouldn't be static?
Well, yes. Although in this particular case, I do not think it is that critical. :)
Also it's often const char * const names[] = { ... } unless you overwrite something.
I tried to use the same type names as in the function prototype. Otherwise the compiler or static analyzer may complain.
+/**
- virtsnd_reset_fn() - Kernel worker's function to reset the device.
- @work: Reset device work.
- Context: Process context.
- */
+static void virtsnd_reset_fn(struct work_struct *work) +{
struct virtio_snd *snd =container_of(work, struct virtio_snd, reset_work);struct virtio_device *vdev = snd->vdev;struct device *dev = &vdev->dev;int rc;dev_info(dev, "sound device needs reset\n");/** It seems that the only way to properly reset the device is to remove* and re-create the ALSA sound card device.*/rc = device_reprobe(dev);if (rc)dev_err(dev, "failed to reprobe sound device: %d\n", rc);Now I'm wondering whether it's safe to do that from this place. Basically device_reprobe() unbinds the device that releases the full resources once including the devm_* stuff. And this work itself is in a part of devm allocated resource, so it'll be released there. That said, we might hit use-after-free... This needs to be verified.
It's safe. Suicide kernel workers are funny but possible things. Since the kernel itself (AFAIU) assumes such a situation and does not access the worker structure after the callback function call.
thanks,
Takashi