+++ /dev/null
-From d4c8a3a4b9de5a25b6963f3ae1b8a5cb32081de5 Mon Sep 17 00:00:00 2001
-From: Anton Yakovlev <anton.yakovlev@opensynergy.com>
-Date: Tue, 2 Mar 2021 17:47:03 +0100
-Subject: [PATCH] ALSA: virtio: handling control messages
-
-The control queue can be used by different parts of the driver to send
-commands to the device. Control messages can be either synchronous or
-asynchronous. The lifetime of a message is controlled by a reference
-count.
-
-Introduce a module parameter to set the message completion timeout:
- msg_timeout_ms [=1000]
-
-Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
-Link: https://lore.kernel.org/r/20210302164709.3142702-4-anton.yakovlev@opensynergy.com
-Signed-off-by: Takashi Iwai <tiwai@suse.de>
-Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@opensynergy.com>
----
- sound/virtio/Makefile | 3 +-
- sound/virtio/virtio_card.c | 13 ++
- sound/virtio/virtio_card.h | 7 +
- sound/virtio/virtio_ctl_msg.c | 310 ++++++++++++++++++++++++++++++++++
- sound/virtio/virtio_ctl_msg.h | 78 +++++++++
- 5 files changed, 410 insertions(+), 1 deletion(-)
- create mode 100644 sound/virtio/virtio_ctl_msg.c
- create mode 100644 sound/virtio/virtio_ctl_msg.h
-
-diff --git a/sound/virtio/Makefile b/sound/virtio/Makefile
-index 8c87ebb9982b..dc551e637441 100644
---- a/sound/virtio/Makefile
-+++ b/sound/virtio/Makefile
-@@ -3,5 +3,6 @@
- obj-$(CONFIG_SND_VIRTIO) += virtio_snd.o
-
- virtio_snd-objs := \
-- virtio_card.o
-+ virtio_card.o \
-+ virtio_ctl_msg.o
-
-diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c
-index 5a37056858e9..b757b2444078 100644
---- a/sound/virtio/virtio_card.c
-+++ b/sound/virtio/virtio_card.c
-@@ -11,6 +11,10 @@
-
- #include "virtio_card.h"
-
-+u32 virtsnd_msg_timeout_ms = MSEC_PER_SEC;
-+module_param_named(msg_timeout_ms, virtsnd_msg_timeout_ms, uint, 0644);
-+MODULE_PARM_DESC(msg_timeout_ms, "Message completion timeout in milliseconds");
-+
- static void virtsnd_remove(struct virtio_device *vdev);
-
- /**
-@@ -96,9 +100,11 @@ static int virtsnd_find_vqs(struct virtio_snd *snd)
- {
- struct virtio_device *vdev = snd->vdev;
- static vq_callback_t *callbacks[VIRTIO_SND_VQ_MAX] = {
-+ [VIRTIO_SND_VQ_CONTROL] = virtsnd_ctl_notify_cb,
- [VIRTIO_SND_VQ_EVENT] = virtsnd_event_notify_cb
- };
- static const char *names[VIRTIO_SND_VQ_MAX] = {
-+ [VIRTIO_SND_VQ_CONTROL] = "virtsnd-ctl",
- [VIRTIO_SND_VQ_EVENT] = "virtsnd-event"
- };
- struct virtqueue *vqs[VIRTIO_SND_VQ_MAX] = { 0 };
-@@ -226,6 +232,11 @@ static int virtsnd_validate(struct virtio_device *vdev)
- return -EINVAL;
- }
-
-+ if (!virtsnd_msg_timeout_ms) {
-+ dev_err(&vdev->dev, "msg_timeout_ms value cannot be zero\n");
-+ return -EINVAL;
-+ }
-+
- return 0;
- }
-
-@@ -247,6 +258,7 @@ static int virtsnd_probe(struct virtio_device *vdev)
- return -ENOMEM;
-
- snd->vdev = vdev;
-+ INIT_LIST_HEAD(&snd->ctl_msgs);
-
- vdev->priv = snd;
-
-@@ -283,6 +295,7 @@ static void virtsnd_remove(struct virtio_device *vdev)
- struct virtio_snd *snd = vdev->priv;
-
- virtsnd_disable_event_vq(snd);
-+ virtsnd_ctl_msg_cancel_all(snd);
-
- if (snd->card)
- snd_card_free(snd->card);
-diff --git a/sound/virtio/virtio_card.h b/sound/virtio/virtio_card.h
-index b903b1b12e90..1e76eeff160f 100644
---- a/sound/virtio/virtio_card.h
-+++ b/sound/virtio/virtio_card.h
-@@ -11,6 +11,8 @@
- #include <sound/core.h>
- #include <uapi/linux/virtio_snd.h>
-
-+#include "virtio_ctl_msg.h"
-+
- #define VIRTIO_SND_CARD_DRIVER "virtio-snd"
- #define VIRTIO_SND_CARD_NAME "VirtIO SoundCard"
-
-@@ -29,15 +31,20 @@ struct virtio_snd_queue {
- * @vdev: Underlying virtio device.
- * @queues: Virtqueue wrappers.
- * @card: ALSA sound card.
-+ * @ctl_msgs: Pending control request list.
- * @event_msgs: Device events.
- */
- struct virtio_snd {
- struct virtio_device *vdev;
- struct virtio_snd_queue queues[VIRTIO_SND_VQ_MAX];
- struct snd_card *card;
-+ struct list_head ctl_msgs;
- struct virtio_snd_event *event_msgs;
- };
-
-+/* Message completion timeout in milliseconds (module parameter). */
-+extern u32 virtsnd_msg_timeout_ms;
-+
- static inline struct virtio_snd_queue *
- virtsnd_control_queue(struct virtio_snd *snd)
- {
-diff --git a/sound/virtio/virtio_ctl_msg.c b/sound/virtio/virtio_ctl_msg.c
-new file mode 100644
-index 000000000000..26ff7e7cc041
---- /dev/null
-+++ b/sound/virtio/virtio_ctl_msg.c
-@@ -0,0 +1,310 @@
-+// SPDX-License-Identifier: GPL-2.0+
-+/*
-+ * virtio-snd: Virtio sound device
-+ * Copyright (C) 2021 OpenSynergy GmbH
-+ */
-+#include <linux/moduleparam.h>
-+#include <linux/virtio_config.h>
-+
-+#include "virtio_card.h"
-+
-+/**
-+ * struct virtio_snd_msg - Control message.
-+ * @sg_request: Scattergather list containing a device request (header).
-+ * @sg_response: Scattergather list containing a device response (status).
-+ * @list: Pending message list entry.
-+ * @notify: Request completed notification.
-+ * @ref_count: Reference count used to manage a message lifetime.
-+ */
-+struct virtio_snd_msg {
-+ struct scatterlist sg_request;
-+ struct scatterlist sg_response;
-+ struct list_head list;
-+ struct completion notify;
-+ refcount_t ref_count;
-+};
-+
-+/**
-+ * virtsnd_ctl_msg_ref() - Increment reference counter for the message.
-+ * @msg: Control message.
-+ *
-+ * Context: Any context.
-+ */
-+void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg)
-+{
-+ refcount_inc(&msg->ref_count);
-+}
-+
-+/**
-+ * virtsnd_ctl_msg_unref() - Decrement reference counter for the message.
-+ * @msg: Control message.
-+ *
-+ * The message will be freed when the ref_count value is 0.
-+ *
-+ * Context: Any context.
-+ */
-+void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg)
-+{
-+ if (refcount_dec_and_test(&msg->ref_count))
-+ kfree(msg);
-+}
-+
-+/**
-+ * virtsnd_ctl_msg_request() - Get a pointer to the request header.
-+ * @msg: Control message.
-+ *
-+ * Context: Any context.
-+ */
-+void *virtsnd_ctl_msg_request(struct virtio_snd_msg *msg)
-+{
-+ return sg_virt(&msg->sg_request);
-+}
-+
-+/**
-+ * virtsnd_ctl_msg_request() - Get a pointer to the response header.
-+ * @msg: Control message.
-+ *
-+ * Context: Any context.
-+ */
-+void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg)
-+{
-+ return sg_virt(&msg->sg_response);
-+}
-+
-+/**
-+ * virtsnd_ctl_msg_alloc() - Allocate and initialize a control message.
-+ * @request_size: Size of request header.
-+ * @response_size: Size of response header.
-+ * @gfp: Kernel flags for memory allocation.
-+ *
-+ * The message will be automatically freed when the ref_count value is 0.
-+ *
-+ * Context: Any context. May sleep if @gfp flags permit.
-+ * Return: Allocated message on success, NULL on failure.
-+ */
-+struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size,
-+ size_t response_size, gfp_t gfp)
-+{
-+ struct virtio_snd_msg *msg;
-+
-+ if (!request_size || !response_size)
-+ return NULL;
-+
-+ msg = kzalloc(sizeof(*msg) + request_size + response_size, gfp);
-+ if (!msg)
-+ return NULL;
-+
-+ sg_init_one(&msg->sg_request, (u8 *)msg + sizeof(*msg), request_size);
-+ sg_init_one(&msg->sg_response, (u8 *)msg + sizeof(*msg) + request_size,
-+ response_size);
-+
-+ INIT_LIST_HEAD(&msg->list);
-+ init_completion(&msg->notify);
-+ /* This reference is dropped in virtsnd_ctl_msg_complete(). */
-+ refcount_set(&msg->ref_count, 1);
-+
-+ return msg;
-+}
-+
-+/**
-+ * virtsnd_ctl_msg_send() - Send a control message.
-+ * @snd: VirtIO sound device.
-+ * @msg: Control message.
-+ * @out_sgs: Additional sg-list to attach to the request header (may be NULL).
-+ * @in_sgs: Additional sg-list to attach to the response header (may be NULL).
-+ * @nowait: Flag indicating whether to wait for completion.
-+ *
-+ * Context: Any context. Takes and releases the control queue spinlock.
-+ * May sleep if @nowait is false.
-+ * Return: 0 on success, -errno on failure.
-+ */
-+int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg,
-+ struct scatterlist *out_sgs,
-+ struct scatterlist *in_sgs, bool nowait)
-+{
-+ struct virtio_device *vdev = snd->vdev;
-+ struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
-+ unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
-+ struct virtio_snd_hdr *request = virtsnd_ctl_msg_request(msg);
-+ struct virtio_snd_hdr *response = virtsnd_ctl_msg_response(msg);
-+ unsigned int nouts = 0;
-+ unsigned int nins = 0;
-+ struct scatterlist *psgs[4];
-+ bool notify = false;
-+ unsigned long flags;
-+ int rc;
-+
-+ virtsnd_ctl_msg_ref(msg);
-+
-+ /* Set the default status in case the message was canceled. */
-+ response->code = cpu_to_le32(VIRTIO_SND_S_IO_ERR);
-+
-+ psgs[nouts++] = &msg->sg_request;
-+ if (out_sgs)
-+ psgs[nouts++] = out_sgs;
-+
-+ psgs[nouts + nins++] = &msg->sg_response;
-+ if (in_sgs)
-+ psgs[nouts + nins++] = in_sgs;
-+
-+ spin_lock_irqsave(&queue->lock, flags);
-+ 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);
-+ }
-+ spin_unlock_irqrestore(&queue->lock, flags);
-+
-+ if (rc) {
-+ dev_err(&vdev->dev, "failed to send control message (0x%08x)\n",
-+ le32_to_cpu(request->code));
-+
-+ /*
-+ * Since in this case virtsnd_ctl_msg_complete() will not be
-+ * called, it is necessary to decrement the reference count.
-+ */
-+ virtsnd_ctl_msg_unref(msg);
-+
-+ goto on_exit;
-+ }
-+
-+ if (notify)
-+ virtqueue_notify(queue->vqueue);
-+
-+ if (nowait)
-+ goto on_exit;
-+
-+ rc = wait_for_completion_interruptible_timeout(&msg->notify, js);
-+ if (rc <= 0) {
-+ if (!rc) {
-+ dev_err(&vdev->dev,
-+ "control message (0x%08x) timeout\n",
-+ le32_to_cpu(request->code));
-+ rc = -ETIMEDOUT;
-+ }
-+
-+ goto on_exit;
-+ }
-+
-+ switch (le32_to_cpu(response->code)) {
-+ case VIRTIO_SND_S_OK:
-+ rc = 0;
-+ break;
-+ case VIRTIO_SND_S_NOT_SUPP:
-+ rc = -EOPNOTSUPP;
-+ break;
-+ case VIRTIO_SND_S_IO_ERR:
-+ rc = -EIO;
-+ break;
-+ default:
-+ rc = -EINVAL;
-+ break;
-+ }
-+
-+on_exit:
-+ virtsnd_ctl_msg_unref(msg);
-+
-+ return rc;
-+}
-+
-+/**
-+ * virtsnd_ctl_msg_complete() - Complete a control message.
-+ * @msg: Control message.
-+ *
-+ * Context: Any context. Expects the control queue spinlock to be held by
-+ * caller.
-+ */
-+void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg)
-+{
-+ list_del(&msg->list);
-+ complete(&msg->notify);
-+
-+ virtsnd_ctl_msg_unref(msg);
-+}
-+
-+/**
-+ * virtsnd_ctl_msg_cancel_all() - Cancel all pending control messages.
-+ * @snd: VirtIO sound device.
-+ *
-+ * Context: Any context.
-+ */
-+void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd)
-+{
-+ struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
-+ unsigned long flags;
-+
-+ spin_lock_irqsave(&queue->lock, flags);
-+ while (!list_empty(&snd->ctl_msgs)) {
-+ struct virtio_snd_msg *msg =
-+ list_first_entry(&snd->ctl_msgs, struct virtio_snd_msg,
-+ list);
-+
-+ virtsnd_ctl_msg_complete(msg);
-+ }
-+ spin_unlock_irqrestore(&queue->lock, flags);
-+}
-+
-+/**
-+ * virtsnd_ctl_query_info() - Query the item configuration from the device.
-+ * @snd: VirtIO sound device.
-+ * @command: Control request code (VIRTIO_SND_R_XXX_INFO).
-+ * @start_id: Item start identifier.
-+ * @count: Item count to query.
-+ * @size: Item information size in bytes.
-+ * @info: Buffer for storing item information.
-+ *
-+ * Context: Any context that permits to sleep.
-+ * Return: 0 on success, -errno on failure.
-+ */
-+int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id,
-+ int count, size_t size, void *info)
-+{
-+ struct virtio_snd_msg *msg;
-+ struct virtio_snd_query_info *query;
-+ struct scatterlist sg;
-+
-+ msg = virtsnd_ctl_msg_alloc(sizeof(*query),
-+ sizeof(struct virtio_snd_hdr), GFP_KERNEL);
-+ if (!msg)
-+ return -ENOMEM;
-+
-+ query = virtsnd_ctl_msg_request(msg);
-+ query->hdr.code = cpu_to_le32(command);
-+ query->start_id = cpu_to_le32(start_id);
-+ query->count = cpu_to_le32(count);
-+ query->size = cpu_to_le32(size);
-+
-+ sg_init_one(&sg, info, count * size);
-+
-+ return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
-+}
-+
-+/**
-+ * virtsnd_ctl_notify_cb() - Process all completed control messages.
-+ * @vqueue: Underlying control virtqueue.
-+ *
-+ * This callback function is called upon a vring interrupt request from the
-+ * device.
-+ *
-+ * Context: Interrupt context. Takes and releases the control queue spinlock.
-+ */
-+void virtsnd_ctl_notify_cb(struct virtqueue *vqueue)
-+{
-+ struct virtio_snd *snd = vqueue->vdev->priv;
-+ struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
-+ struct virtio_snd_msg *msg;
-+ u32 length;
-+ unsigned long flags;
-+
-+ spin_lock_irqsave(&queue->lock, flags);
-+ do {
-+ virtqueue_disable_cb(vqueue);
-+ while ((msg = virtqueue_get_buf(vqueue, &length)))
-+ virtsnd_ctl_msg_complete(msg);
-+ if (unlikely(virtqueue_is_broken(vqueue)))
-+ break;
-+ } while (!virtqueue_enable_cb(vqueue));
-+ spin_unlock_irqrestore(&queue->lock, flags);
-+}
-diff --git a/sound/virtio/virtio_ctl_msg.h b/sound/virtio/virtio_ctl_msg.h
-new file mode 100644
-index 000000000000..7f4db044f28e
---- /dev/null
-+++ b/sound/virtio/virtio_ctl_msg.h
-@@ -0,0 +1,78 @@
-+/* SPDX-License-Identifier: GPL-2.0+ */
-+/*
-+ * virtio-snd: Virtio sound device
-+ * Copyright (C) 2021 OpenSynergy GmbH
-+ */
-+#ifndef VIRTIO_SND_MSG_H
-+#define VIRTIO_SND_MSG_H
-+
-+#include <linux/atomic.h>
-+#include <linux/virtio.h>
-+
-+struct virtio_snd;
-+struct virtio_snd_msg;
-+
-+void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg);
-+
-+void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg);
-+
-+void *virtsnd_ctl_msg_request(struct virtio_snd_msg *msg);
-+
-+void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg);
-+
-+struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size,
-+ size_t response_size, gfp_t gfp);
-+
-+int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg,
-+ struct scatterlist *out_sgs,
-+ struct scatterlist *in_sgs, bool nowait);
-+
-+/**
-+ * virtsnd_ctl_msg_send_sync() - Simplified sending of synchronous message.
-+ * @snd: VirtIO sound device.
-+ * @msg: Control message.
-+ *
-+ * After returning from this function, the message will be deleted. If message
-+ * content is still needed, the caller must additionally to
-+ * virtsnd_ctl_msg_ref/unref() it.
-+ *
-+ * The msg_timeout_ms module parameter defines the message completion timeout.
-+ * If the message is not completed within this time, the function will return an
-+ * error.
-+ *
-+ * Context: Any context that permits to sleep.
-+ * Return: 0 on success, -errno on failure.
-+ *
-+ * The return value is a message status code (VIRTIO_SND_S_XXX) converted to an
-+ * appropriate -errno value.
-+ */
-+static inline int virtsnd_ctl_msg_send_sync(struct virtio_snd *snd,
-+ struct virtio_snd_msg *msg)
-+{
-+ return virtsnd_ctl_msg_send(snd, msg, NULL, NULL, false);
-+}
-+
-+/**
-+ * virtsnd_ctl_msg_send_async() - Simplified sending of asynchronous message.
-+ * @snd: VirtIO sound device.
-+ * @msg: Control message.
-+ *
-+ * Context: Any context.
-+ * Return: 0 on success, -errno on failure.
-+ */
-+static inline int virtsnd_ctl_msg_send_async(struct virtio_snd *snd,
-+ struct virtio_snd_msg *msg)
-+{
-+ return virtsnd_ctl_msg_send(snd, msg, NULL, NULL, true);
-+}
-+
-+void virtsnd_ctl_msg_cancel_all(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,
-+ int count, size_t size, void *info);
-+
-+void virtsnd_ctl_notify_cb(struct virtqueue *vqueue);
-+
-+#endif /* VIRTIO_SND_MSG_H */
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