[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: Re: [PATCH v5 2/9] ALSA: virtio: add virtio sound driver
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
-- Anton Yakovlev Senior Software Engineer OpenSynergy GmbH Rotherstr. 20, 10245 Berlin
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]