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Mon, 02 Nov 2026 16:04:19 -0800 (PST) Received: from localhost.localdomain ([183.96.175.225]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3b07c6b3493sm1339225a91.13.2026.11.02.16.04.16 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 02 Nov 2026 16:04:18 -0800 (PST) From: Joonho Lee To: linux-sound@vger.kernel.org Cc: tiwai@suse.de, perex@perex.cz, anton.yakovlev@opensynergy.com, mst@redhat.com, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, corbet@lwn.net, skhan@linuxfoundation.org, rdunlap@infradead.org, linux-doc@vger.kernel.org, Joonho Lee Subject: [PATCH v12 03/12] ALSA: virtio: Retain queued messages through device reset Date: Tue, 3 Nov 2026 09:03:54 +0900 Message-ID: <20261103000403.67106-4-mynameisjune111@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20261103000403.67106-1-mynameisjune111@gmail.com> References: <20261103000403.67106-1-mynameisjune111@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Keep the control queue available through snd_card_free() so close-time STOP and RELEASE commands can still be submitted. Block new control requests and mark pending messages canceled before reset, then release their queue references only after reset and queue deletion. For PCM queues, detach each remaining virtqueue buffer after the device has stopped DMA and retire its message without reporting a normal completion. Detach all queues before deleting them so outstanding DMA mappings are unmapped and no token remains for a late device completion. Clear each queue wrapper inside the same critical section that detaches its buffers. Check the callback's queue identity under the wrapper lock for PCM, control and event queues. This makes queue retirement explicit through teardown and restore. A forced callback test passed on both versions; the proposed detached-ring IRQ failure was not reproduced on the tested PCI transport. Fixes: 9d45e514da88 ("ALSA: virtio: handling control messages") Assisted-by: LLM Signed-off-by: Joonho Lee --- diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c --- a/sound/virtio/virtio_card.c +++ b/sound/virtio/virtio_card.c @@ -87,6 +87,8 @@ u32 length; guard(spinlock_irqsave)(&queue->lock); + if (queue->vqueue != vqueue) + return; do { virtqueue_disable_cb(vqueue); while ((event = virtqueue_get_buf(vqueue, &length))) { @@ -338,6 +340,38 @@ } /** + * virtsnd_reset_vqs() - Stop device access and unmap outstanding buffers. + * @snd: VirtIO sound device. + * + * Context: Any context that permits to sleep. + */ +static void virtsnd_reset_vqs(struct virtio_snd *snd) +{ + struct virtio_device *vdev = snd->vdev; + unsigned int i; + + virtio_reset_device(vdev); + + /* Deleting a virtqueue does not unmap its outstanding descriptors. */ + for (i = 0; i < VIRTIO_SND_VQ_MAX; ++i) { + struct virtio_snd_queue *queue = &snd->queues[i]; + unsigned long flags; + void *msg; + + spin_lock_irqsave(&queue->lock, flags); + if (queue->vqueue) + while ((msg = virtqueue_detach_unused_buf(queue->vqueue))) + if (i == VIRTIO_SND_VQ_TX || i == VIRTIO_SND_VQ_RX) + virtsnd_pcm_msg_cancel(msg); + /* IRQ callbacks must never see a detached ring as live. */ + queue->vqueue = NULL; + spin_unlock_irqrestore(&queue->lock, flags); + } + + vdev->config->del_vqs(vdev); +} + +/** * virtsnd_remove() - Remove VirtIO and ALSA devices. * @vdev: VirtIO parent device. * @@ -349,13 +383,14 @@ unsigned int i; virtsnd_disable_event_vq(snd); - virtsnd_ctl_msg_cancel_all(snd); if (snd->card) snd_card_free(snd->card); - virtio_reset_device(vdev); - vdev->config->del_vqs(vdev); + virtsnd_ctl_msg_cancel_all(snd); + + virtsnd_reset_vqs(snd); + virtsnd_ctl_msg_cleanup(snd); for (i = 0; snd->substreams && i < snd->nsubstreams; ++i) { struct virtio_pcm_substream *vss = &snd->substreams[i]; @@ -383,8 +418,8 @@ virtsnd_disable_event_vq(snd); virtsnd_ctl_msg_cancel_all(snd); - virtio_reset_device(vdev); - vdev->config->del_vqs(vdev); + virtsnd_reset_vqs(snd); + virtsnd_ctl_msg_cleanup(snd); for (i = 0; i < snd->nsubstreams; ++i) cancel_work_sync(&snd->substreams[i].elapsed_period); @@ -412,6 +447,7 @@ return rc; virtio_device_ready(vdev); + virtsnd_ctl_msg_enable(snd); virtsnd_enable_event_vq(snd); diff --git a/sound/virtio/virtio_card.h b/sound/virtio/virtio_card.h --- a/sound/virtio/virtio_card.h +++ b/sound/virtio/virtio_card.h @@ -47,6 +47,7 @@ * @queues: Virtqueue wrappers. * @card: ALSA sound card. * @ctl_msgs: Pending control request list. + * @ctl_msgs_blocked: Control requests are blocked during teardown or suspend. * @event_msgs: Device events. * @pcm_list: VirtIO PCM device list. * @jacks: VirtIO jacks. @@ -64,6 +65,7 @@ struct virtio_snd_queue queues[VIRTIO_SND_VQ_MAX]; struct snd_card *card; struct list_head ctl_msgs; + bool ctl_msgs_blocked; struct virtio_snd_event *event_msgs; struct list_head pcm_list; struct virtio_jack *jacks; diff --git a/sound/virtio/virtio_ctl_msg.c b/sound/virtio/virtio_ctl_msg.c --- a/sound/virtio/virtio_ctl_msg.c +++ b/sound/virtio/virtio_ctl_msg.c @@ -15,6 +15,7 @@ * @list: Pending message list entry. * @notify: Request completed notification. * @ref_count: Reference count used to manage a message lifetime. + * @cancelled: Request canceled during device teardown. */ struct virtio_snd_msg { struct scatterlist sg_request; @@ -22,6 +23,7 @@ struct list_head list; struct completion notify; refcount_t ref_count; + bool cancelled; }; /** @@ -100,7 +102,7 @@ INIT_LIST_HEAD(&msg->list); init_completion(&msg->notify); - /* This reference is dropped in virtsnd_ctl_msg_complete(). */ + /* The caller owns this reference; send adds a queue reference. */ refcount_set(&msg->ref_count, 1); return msg; @@ -134,6 +136,7 @@ int rc; virtsnd_ctl_msg_ref(msg); + /* This reference stays with the queue until completion or teardown. */ /* Set the default status in case the message was canceled. */ response->code = cpu_to_le32(VIRTIO_SND_S_IO_ERR); @@ -147,12 +150,17 @@ psgs[nouts + nins++] = in_sgs; scoped_guard(spinlock_irqsave, &queue->lock) { - rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg, - GFP_ATOMIC); + if (snd->ctl_msgs_blocked) + rc = -ENODEV; + else + rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, + msg, GFP_ATOMIC); if (!rc) { notify = virtqueue_kick_prepare(queue->vqueue); list_add_tail(&msg->list, &snd->ctl_msgs); + if (notify) + virtqueue_notify(queue->vqueue); } } @@ -168,9 +176,6 @@ goto on_exit; } - - if (notify) - virtqueue_notify(queue->vqueue); if (nowait) goto on_exit; @@ -184,6 +189,11 @@ rc = -ETIMEDOUT; } + goto on_exit; + } + + if (READ_ONCE(msg->cancelled)) { + rc = -ENODEV; goto on_exit; } @@ -227,9 +237,33 @@ * virtsnd_ctl_msg_cancel_all() - Cancel all pending control messages. * @snd: VirtIO sound device. * - * Context: Any context. + * Context: Any context. Blocks new senders and marks pending requests canceled. + * Existing senders are woken when their request completes or after + * the device has been reset. */ void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd) +{ + struct virtio_snd_queue *queue = virtsnd_control_queue(snd); + struct virtio_snd_msg *msg; + + guard(spinlock_irqsave)(&queue->lock); + snd->ctl_msgs_blocked = true; + list_for_each_entry(msg, &snd->ctl_msgs, list) { + WRITE_ONCE(msg->cancelled, true); + } +} + +/** + * virtsnd_ctl_msg_cleanup() - Release messages left after queue teardown. + * @snd: VirtIO sound device. + * + * This must be called after device reset, buffer detachment, and del_vqs(), + * when no queue callback or DMA access can still reach a message. The queue + * object and its lock must remain alive until this function returns. + * + * Context: Any context. + */ +void virtsnd_ctl_msg_cleanup(struct virtio_snd *snd) { struct virtio_snd_queue *queue = virtsnd_control_queue(snd); @@ -244,6 +278,20 @@ } /** + * virtsnd_ctl_msg_enable() - Allow control requests after queue restoration. + * @snd: VirtIO sound device. + * + * Context: Any context. + */ +void virtsnd_ctl_msg_enable(struct virtio_snd *snd) +{ + struct virtio_snd_queue *queue = virtsnd_control_queue(snd); + + guard(spinlock_irqsave)(&queue->lock); + snd->ctl_msgs_blocked = false; +} + +/** * virtsnd_ctl_query_info() - Query the item configuration from the device. * @snd: VirtIO sound device. * @command: Control request code (VIRTIO_SND_R_XXX_INFO). @@ -295,6 +343,8 @@ u32 length; guard(spinlock_irqsave)(&queue->lock); + if (queue->vqueue != vqueue) + return; do { virtqueue_disable_cb(vqueue); while ((msg = virtqueue_get_buf(vqueue, &length))) diff --git a/sound/virtio/virtio_ctl_msg.h b/sound/virtio/virtio_ctl_msg.h --- a/sound/virtio/virtio_ctl_msg.h +++ b/sound/virtio/virtio_ctl_msg.h @@ -68,6 +68,10 @@ void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd); +void virtsnd_ctl_msg_cleanup(struct virtio_snd *snd); + +void virtsnd_ctl_msg_enable(struct virtio_snd *snd); + void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg); int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id, diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h --- a/sound/virtio/virtio_pcm.h +++ b/sound/virtio/virtio_pcm.h @@ -122,6 +122,8 @@ void virtsnd_pcm_msg_reset(struct virtio_pcm_substream *vss); +void virtsnd_pcm_msg_cancel(struct virtio_pcm_msg *msg); + int virtsnd_pcm_msg_send(struct virtio_pcm_substream *vss, unsigned long offset, unsigned long bytes); diff --git a/sound/virtio/virtio_pcm_msg.c b/sound/virtio/virtio_pcm_msg.c --- a/sound/virtio/virtio_pcm_msg.c +++ b/sound/virtio/virtio_pcm_msg.c @@ -305,6 +305,35 @@ { guard(spinlock_irqsave)(&vss->lock); return vss->msg_count; +} + +/** + * virtsnd_pcm_msg_cancel() - Cancel a message detached during device reset. + * @msg: Message returned by virtqueue_detach_unused_buf(). + * + * Reset cancellation retires the queue token without treating it as a device + * completion. In particular, it does not advance the PCM hardware pointer or + * schedule period work. + * + * Context: Process context with the PCM queue lock held. + */ +void virtsnd_pcm_msg_cancel(struct virtio_pcm_msg *msg) +{ + struct virtio_pcm_substream *vss = msg->substream; + bool wake; + + { + guard(spinlock)(&vss->lock); + msg->length = 0; + vss->xfer_enabled = false; + if (WARN_ON_ONCE(!vss->msg_count)) + return; + vss->msg_count--; + wake = !vss->msg_count; + } + + if (wake) + wake_up_all(&vss->msg_empty); } /** @@ -367,16 +396,21 @@ /** * virtsnd_pcm_notify_cb() - Process all completed I/O messages. - * @queue: Underlying tx/rx virtqueue. + * @queue: Underlying tx/rx queue wrapper. + * @vqueue: Queue that raised this callback. * * Context: Interrupt context. Takes and releases the tx/rx queue spinlock. */ -static inline void virtsnd_pcm_notify_cb(struct virtio_snd_queue *queue) +static inline void +virtsnd_pcm_notify_cb(struct virtio_snd_queue *queue, struct virtqueue *vqueue) { struct virtio_pcm_msg *msg; u32 written_bytes; guard(spinlock_irqsave)(&queue->lock); + /* Reset can detach the queue before the transport drains its IRQs. */ + if (queue->vqueue != vqueue) + return; do { virtqueue_disable_cb(queue->vqueue); while ((msg = virtqueue_get_buf(queue->vqueue, &written_bytes))) @@ -394,7 +428,7 @@ { struct virtio_snd *snd = vqueue->vdev->priv; - virtsnd_pcm_notify_cb(virtsnd_tx_queue(snd)); + virtsnd_pcm_notify_cb(virtsnd_tx_queue(snd), vqueue); } /** @@ -407,7 +441,7 @@ { struct virtio_snd *snd = vqueue->vdev->priv; - virtsnd_pcm_notify_cb(virtsnd_rx_queue(snd)); + virtsnd_pcm_notify_cb(virtsnd_rx_queue(snd), vqueue); } /**