Re: [PATCH 1/3] virtio: find_vqs/del_vqs virtio operations

Rusty Russell
2009-05-08T07:07:25Z

On Thu, 7 May 2009 11:40:39 pm Michael S. Tsirkin wrote:
> This replaces find_vq/del_vq with find_vqs/del_vqs virtio operations,
> and updates all drivers. This is needed for MSI support, because MSI
> needs to know the total number of vectors upfront.

Hmm, I have a similar need for a dev to vq mapping (debugging stats). How's
this as a common basis?

Thanks,
Rusty.

virtio: add names to virtqueue struct, mapping from devices to queues.

Add a linked list of all virtqueues for a virtio device: this helps for
debugging and is also needed for upcoming interface change.

Also, add a "name" field for clearer debug messages.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
drivers/block/virtio_blk.c | 2 +-
drivers/char/hw_random/virtio-rng.c | 2 +-
drivers/char/virtio_console.c | 4 ++--
drivers/lguest/lguest_device.c | 5 +++--
drivers/net/virtio_net.c | 6 +++---
drivers/s390/kvm/kvm_virtio.c | 7 ++++---
drivers/virtio/virtio.c | 2 ++
drivers/virtio/virtio_balloon.c | 4 ++--
drivers/virtio/virtio_pci.c | 5 +++--
drivers/virtio/virtio_ring.c | 25 +++++++++++++++++++------
include/linux/virtio.h | 12 ++++++++----
include/linux/virtio_config.h | 6 ++++--
include/linux/virtio_ring.h | 3 ++-
net/9p/trans_virtio.c | 2 +-
14 files changed, 55 insertions(+), 30 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -224,7 +224,7 @@ static int virtblk_probe(struct virtio_d
sg_init_table(vblk->sg, vblk->sg_elems);

/* We expect one virtqueue, for output. */
- vblk->vq = vdev->config->find_vq(vdev, 0, blk_done);
+ vblk->vq = vdev->config->find_vq(vdev, 0, blk_done, "requests");
if (IS_ERR(vblk->vq)) {
err = PTR_ERR(vblk->vq);
goto out_free_vblk;
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -94,7 +94,7 @@ static int virtrng_probe(struct virtio_d
int err;

/* We expect a single virtqueue. */
- vq = vdev->config->find_vq(vdev, 0, random_recv_done);
+ vq = vdev->config->find_vq(vdev, 0, random_recv_done, "input");
if (IS_ERR(vq))
return PTR_ERR(vq);

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -202,13 +202,13 @@ static int __devinit virtcons_probe(stru
/* Find the input queue. */
/* FIXME: This is why we want to wean off hvc: we do nothing
* when input comes in. */
- in_vq = vdev->config->find_vq(vdev, 0, hvc_handle_input);
+ in_vq = vdev->config->find_vq(vdev, 0, hvc_handle_input, "input");
if (IS_ERR(in_vq)) {
err = PTR_ERR(in_vq);
goto free;
}

- out_vq = vdev->config->find_vq(vdev, 1, NULL);
+ out_vq = vdev->config->find_vq(vdev, 1, NULL, "output");
if (IS_ERR(out_vq)) {
err = PTR_ERR(out_vq);
goto free_in_vq;
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -228,7 +228,8 @@ extern void lguest_setup_irq(unsigned in
* function. */
static struct virtqueue *lg_find_vq(struct virtio_device *vdev,
unsigned index,
- void (*callback)(struct virtqueue *vq))
+ void (*callback)(struct virtqueue *vq),
+ const char *name)
{
struct lguest_device *ldev = to_lgdev(vdev);
struct lguest_vq_info *lvq;
@@ -263,7 +264,7 @@ static struct virtqueue *lg_find_vq(stru
/* OK, tell virtio_ring.c to set up a virtqueue now we know its size
* and we've got a pointer to its pages. */
vq = vring_new_virtqueue(lvq->config.num, LGUEST_VRING_ALIGN,
- vdev, lvq->pages, lg_notify, callback);
+ vdev, lvq->pages, lg_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto unmap;
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -902,20 +902,20 @@ static int virtnet_probe(struct virtio_d
vi->mergeable_rx_bufs = true;

/* We expect two virtqueues, receive then send. */
- vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
+ vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done, "input");
if (IS_ERR(vi->rvq)) {
err = PTR_ERR(vi->rvq);
goto free;
}

- vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
+ vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done, "output");
if (IS_ERR(vi->svq)) {
err = PTR_ERR(vi->svq);
goto free_recv;
}

if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
- vi->cvq = vdev->config->find_vq(vdev, 2, NULL);
+ vi->cvq = vdev->config->find_vq(vdev, 2, NULL, "control");
if (IS_ERR(vi->cvq)) {
err = PTR_ERR(vi->svq);
goto free_send;
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -173,8 +173,9 @@ static void kvm_notify(struct virtqueue
* this device and sets it up.
*/
static struct virtqueue *kvm_find_vq(struct virtio_device *vdev,
- unsigned index,
- void (*callback)(struct virtqueue *vq))
+ unsigned index,
+ void (*callback)(struct virtqueue *vq),
+ const char *name)
{
struct kvm_device *kdev = to_kvmdev(vdev);
struct kvm_vqconfig *config;
@@ -194,7 +195,7 @@ static struct virtqueue *kvm_find_vq(str

vq = vring_new_virtqueue(config->num, KVM_S390_VIRTIO_RING_ALIGN,
vdev, (void *) config->address,
- kvm_notify, callback);
+ kvm_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto unmap;
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -186,6 +186,8 @@ int register_virtio_device(struct virtio
/* Acknowledge that we've seen the device. */
add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);

+ INIT_LIST_HEAD(&dev->vqs);
+
/* device_register() causes the bus infrastructure to look for a
* matching driver. */
err = device_register(&dev->dev);
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -218,13 +218,13 @@ static int virtballoon_probe(struct virt
vb->vdev = vdev;

/* We expect two virtqueues. */
- vb->inflate_vq = vdev->config->find_vq(vdev, 0, balloon_ack);
+ vb->inflate_vq = vdev->config->find_vq(vdev, 0, balloon_ack, "inflate");
if (IS_ERR(vb->inflate_vq)) {
err = PTR_ERR(vb->inflate_vq);
goto out_free_vb;
}

- vb->deflate_vq = vdev->config->find_vq(vdev, 1, balloon_ack);
+ vb->deflate_vq = vdev->config->find_vq(vdev, 1, balloon_ack, "deflate");
if (IS_ERR(vb->deflate_vq)) {
err = PTR_ERR(vb->deflate_vq);
goto out_del_inflate_vq;
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -208,7 +208,8 @@ static irqreturn_t vp_interrupt(int irq,

/* the config->find_vq() implementation */
static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
- void (*callback)(struct virtqueue *vq))
+ void (*callback)(struct virtqueue *vq),
+ const char *name)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
struct virtio_pci_vq_info *info;
@@ -247,7 +248,7 @@ static struct virtqueue *vp_find_vq(stru

/* create the vring */
vq = vring_new_virtqueue(info->num, VIRTIO_PCI_VRING_ALIGN,
- vdev, info->queue, vp_notify, callback);
+ vdev, info->queue, vp_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto out_activate_queue;
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -23,21 +23,30 @@

#ifdef DEBUG
/* For development, we want to crash whenever the ring is screwed. */
-#define BAD_RING(_vq, fmt...) \
- do { dev_err(&(_vq)->vq.vdev->dev, fmt); BUG(); } while(0)
+#define BAD_RING(_vq, fmt, args...) \
+ do { \
+ dev_err(&(_vq)->vq.vdev->dev, \
+ "%s:"fmt, (_vq)->vq.name, ##args); \
+ BUG(); \
+ } while (0)
/* Caller is supposed to guarantee no reentry. */
#define START_USE(_vq) \
do { \
if ((_vq)->in_use) \
- panic("in_use = %i\n", (_vq)->in_use); \
+ panic("%s:in_use = %i\n", \
+ (_vq)->vq.name, (_vq)->in_use); \
(_vq)->in_use = __LINE__; \
mb(); \
} while (0)
#define END_USE(_vq) \
do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; mb(); } while(0)
#else
-#define BAD_RING(_vq, fmt...) \
- do { dev_err(&_vq->vq.vdev->dev, fmt); (_vq)->broken = true; } while(0)
+#define BAD_RING(_vq, fmt, args...) \
+ do { \
+ dev_err(&_vq->vq.vdev->dev, \
+ "%s:"fmt, (_vq)->vq.name, ##args); \
+ (_vq)->broken = true; \
+ } while(0)
#define START_USE(vq)
#define END_USE(vq)
#endif
@@ -284,7 +293,8 @@ struct virtqueue *vring_new_virtqueue(un
struct virtio_device *vdev,
void *pages,
void (*notify)(struct virtqueue *),
- void (*callback)(struct virtqueue *))
+ void (*callback)(struct virtqueue *),
+ const char *name)
{
struct vring_virtqueue *vq;
unsigned int i;
@@ -303,10 +313,12 @@ struct virtqueue *vring_new_virtqueue(un
vq->vq.callback = callback;
vq->vq.vdev = vdev;
vq->vq.vq_ops = &vring_vq_ops;
+ vq->vq.name = name;
vq->notify = notify;
vq->broken = false;
vq->last_used_idx = 0;
vq->num_added = 0;
+ list_add_tail(&vq->vq.list, &vdev->vqs);
#ifdef DEBUG
vq->in_use = false;
#endif
@@ -327,6 +339,7 @@ EXPORT_SYMBOL_GPL(vring_new_virtqueue);

void vring_del_virtqueue(struct virtqueue *vq)
{
+ list_del(&vq->list);
kfree(to_vvq(vq));
}
EXPORT_SYMBOL_GPL(vring_del_virtqueue);
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -10,14 +10,17 @@

/**
* virtqueue - a queue to register buffers for sending or receiving.
+ * @list: the chain of virtqueues for this device
* @callback: the function to call when buffers are consumed (can be NULL).
+ * @name: the name of this virtqueue (mainly for debugging)
* @vdev: the virtio device this queue was created for.
* @vq_ops: the operations for this virtqueue (see below).
* @priv: a pointer for the virtqueue implementation to use.
*/
-struct virtqueue
-{
+struct virtqueue {
+ struct list_head list;
void (*callback)(struct virtqueue *vq);
+ const char *name;
struct virtio_device *vdev;
struct virtqueue_ops *vq_ops;
void *priv;
@@ -76,15 +79,16 @@ struct virtqueue_ops {
* @dev: underlying device.
* @id: the device type identification (used to match it with a driver).
* @config: the configuration ops for this device.
+ * @vqs: the list of virtqueues for this device.
* @features: the features supported by both driver and device.
* @priv: private pointer for the driver's use.
*/
-struct virtio_device
-{
+struct virtio_device {
int index;
struct device dev;
struct virtio_device_id id;
struct virtio_config_ops *config;
+ struct list_head vqs;
/* Note that this is a Linux set_bit-style bitmap. */
unsigned long features[1];
void *priv;
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -55,7 +55,8 @@
* @find_vq: find a virtqueue and instantiate it.
* vdev: the virtio_device
* index: the 0-based virtqueue number in case there's more than one.
- * callback: the virqtueue callback
+ * callback: the virtqueue callback
+ * name: the virtqueue name (mainly for debugging)
* Returns the new virtqueue or ERR_PTR() (eg. -ENOENT).
* @del_vq: free a virtqueue found by find_vq().
* @get_features: get the array of feature bits for this device.
@@ -77,7 +78,8 @@ struct virtio_config_ops
void (*reset)(struct virtio_device *vdev);
struct virtqueue *(*find_vq)(struct virtio_device *vdev,
unsigned index,
- void (*callback)(struct virtqueue *));
+ void (*callback)(struct virtqueue *),
+ const char *name);
void (*del_vq)(struct virtqueue *vq);
u32 (*get_features)(struct virtio_device *vdev);
void (*finalize_features)(struct virtio_device *vdev);
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -119,7 +119,8 @@ struct virtqueue *vring_new_virtqueue(un
struct virtio_device *vdev,
void *pages,
void (*notify)(struct virtqueue *vq),
- void (*callback)(struct virtqueue *vq));
+ void (*callback)(struct virtqueue *vq),
+ const char *name);
void vring_del_virtqueue(struct virtqueue *vq);
/* Filter out transport-specific feature bits. */
void vring_transport_features(struct virtio_device *vdev);
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -245,7 +245,7 @@ static int p9_virtio_probe(struct virtio
chan->vdev = vdev;

/* We expect one virtqueue, for requests. */
- chan->vq = vdev->config->find_vq(vdev, 0, req_done);
+ chan->vq = vdev->config->find_vq(vdev, 0, req_done, "requests");
if (IS_ERR(chan->vq)) {
err = PTR_ERR(chan->vq);
goto out_free_vq;