Re: [PATCH 1/9] virtio_pci: remove struct virtio_pci_vq_info

[Jason Wang <jasowang@xxxxxxxxxx>]

On 2017年02月07日 17:38, Christoph Hellwig wrote:
> On Tue, Feb 07, 2017 at 03:17:02PM +0800, Jason Wang wrote:
> > The check is still there.
> Meh, I could swear I fixed it up.  Here is an updated version:
>
> ---
>  From bf5e3b7fd272aea32388570503f00d0ab592fc2a Mon Sep 17 00:00:00 2001
> From: Christoph Hellwig <hch@xxxxxx>
> Date: Wed, 25 Jan 2017 13:40:21 +0100
> Subject: virtio_pci: remove struct virtio_pci_vq_info
>
> We don't really need struct virtio_pci_vq_info, as most field in there
> are redundant:
>
>   - the vq backpointer is not strictly neede to start with
>   - the entry in the vqs list is not needed - the generic virtqueue already
>     has list, we only need to check if it has a callback to get the same
>     semantics
>   - we can use a simple array to look up the MSI-X vec if needed.
>   - That simple array now also duoble serves to replace the per_vq_vectors
>     flag
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Reviewed-by: Jason Wang <jasowang@xxxxxxxxxx>

> ---
>   drivers/virtio/virtio_pci_common.c | 117 +++++++++++--------------------------
>   drivers/virtio/virtio_pci_common.h |  25 +-------
>   drivers/virtio/virtio_pci_legacy.c |   6 +-
>   drivers/virtio/virtio_pci_modern.c |   6 +-
>   4 files changed, 39 insertions(+), 115 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index 186cbab327b8..1f9fac7dad61 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -62,16 +62,13 @@ static irqreturn_t vp_config_changed(int irq, void *opaque)
>   static irqreturn_t vp_vring_interrupt(int irq, void *opaque)
>   {
>   	struct virtio_pci_device *vp_dev = opaque;
> -	struct virtio_pci_vq_info *info;
>   	irqreturn_t ret = IRQ_NONE;
> -	unsigned long flags;
> +	struct virtqueue *vq;
>   
> -	spin_lock_irqsave(&vp_dev->lock, flags);
> -	list_for_each_entry(info, &vp_dev->virtqueues, node) {
> -		if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
> +	list_for_each_entry(vq, &vp_dev->vdev.vqs, list) {
> +		if (vring_interrupt(irq, vq) == IRQ_HANDLED)
>   			ret = IRQ_HANDLED;
>   	}
> -	spin_unlock_irqrestore(&vp_dev->lock, flags);
>   
>   	return ret;
>   }
> @@ -167,55 +164,6 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
>   	return err;
>   }
>   
> -static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
> -				     void (*callback)(struct virtqueue *vq),
> -				     const char *name,
> -				     u16 msix_vec)
> -{
> -	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> -	struct virtio_pci_vq_info *info = kmalloc(sizeof *info, GFP_KERNEL);
> -	struct virtqueue *vq;
> -	unsigned long flags;
> -
> -	/* fill out our structure that represents an active queue */
> -	if (!info)
> -		return ERR_PTR(-ENOMEM);
> -
> -	vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, msix_vec);
> -	if (IS_ERR(vq))
> -		goto out_info;
> -
> -	info->vq = vq;
> -	if (callback) {
> -		spin_lock_irqsave(&vp_dev->lock, flags);
> -		list_add(&info->node, &vp_dev->virtqueues);
> -		spin_unlock_irqrestore(&vp_dev->lock, flags);
> -	} else {
> -		INIT_LIST_HEAD(&info->node);
> -	}
> -
> -	vp_dev->vqs[index] = info;
> -	return vq;
> -
> -out_info:
> -	kfree(info);
> -	return vq;
> -}
> -
> -static void vp_del_vq(struct virtqueue *vq)
> -{
> -	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
> -	struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&vp_dev->lock, flags);
> -	list_del(&info->node);
> -	spin_unlock_irqrestore(&vp_dev->lock, flags);
> -
> -	vp_dev->del_vq(info);
> -	kfree(info);
> -}
> -
>   /* the config->del_vqs() implementation */
>   void vp_del_vqs(struct virtio_device *vdev)
>   {
> @@ -224,16 +172,15 @@ void vp_del_vqs(struct virtio_device *vdev)
>   	int i;
>   
>   	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
> -		if (vp_dev->per_vq_vectors) {
> -			int v = vp_dev->vqs[vq->index]->msix_vector;
> +		if (vp_dev->msix_vector_map) {
> +			int v = vp_dev->msix_vector_map[vq->index];
>   
>   			if (v != VIRTIO_MSI_NO_VECTOR)
>   				free_irq(pci_irq_vector(vp_dev->pci_dev, v),
>   					vq);
>   		}
> -		vp_del_vq(vq);
> +		vp_dev->del_vq(vq);
>   	}
> -	vp_dev->per_vq_vectors = false;
>   
>   	if (vp_dev->intx_enabled) {
>   		free_irq(vp_dev->pci_dev->irq, vp_dev);
> @@ -261,8 +208,8 @@ void vp_del_vqs(struct virtio_device *vdev)
>   	vp_dev->msix_names = NULL;
>   	kfree(vp_dev->msix_affinity_masks);
>   	vp_dev->msix_affinity_masks = NULL;
> -	kfree(vp_dev->vqs);
> -	vp_dev->vqs = NULL;
> +	kfree(vp_dev->msix_vector_map);
> +	vp_dev->msix_vector_map = NULL;
>   }
>   
>   static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
> @@ -275,10 +222,6 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
>   	u16 msix_vec;
>   	int i, err, nvectors, allocated_vectors;
>   
> -	vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
> -	if (!vp_dev->vqs)
> -		return -ENOMEM;
> -
>   	if (per_vq_vectors) {
>   		/* Best option: one for change interrupt, one per vq. */
>   		nvectors = 1;
> @@ -294,7 +237,13 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
>   	if (err)
>   		goto error_find;
>   
> -	vp_dev->per_vq_vectors = per_vq_vectors;
> +	if (per_vq_vectors) {
> +		vp_dev->msix_vector_map = kmalloc_array(nvqs,
> +				sizeof(*vp_dev->msix_vector_map), GFP_KERNEL);
> +		if (!vp_dev->msix_vector_map)
> +			goto error_find;
> +	}
> +
>   	allocated_vectors = vp_dev->msix_used_vectors;
>   	for (i = 0; i < nvqs; ++i) {
>   		if (!names[i]) {
> @@ -304,19 +253,25 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
>   
>   		if (!callbacks[i])
>   			msix_vec = VIRTIO_MSI_NO_VECTOR;
> -		else if (vp_dev->per_vq_vectors)
> +		else if (per_vq_vectors)
>   			msix_vec = allocated_vectors++;
>   		else
>   			msix_vec = VP_MSIX_VQ_VECTOR;
> -		vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i], msix_vec);
> +		vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i],
> +				msix_vec);
>   		if (IS_ERR(vqs[i])) {
>   			err = PTR_ERR(vqs[i]);
>   			goto error_find;
>   		}
>   
> -		if (!vp_dev->per_vq_vectors || msix_vec == VIRTIO_MSI_NO_VECTOR)
> +		if (!per_vq_vectors)
>   			continue;
>   
> +		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
> +			vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
> +			continue;
> +		}
> +
>   		/* allocate per-vq irq if available and necessary */
>   		snprintf(vp_dev->msix_names[msix_vec],
>   			 sizeof *vp_dev->msix_names,
> @@ -326,8 +281,12 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
>   				  vring_interrupt, 0,
>   				  vp_dev->msix_names[msix_vec],
>   				  vqs[i]);
> -		if (err)
> +		if (err) {
> +			/* don't free this irq on error */
> +			vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
>   			goto error_find;
> +		}
> +		vp_dev->msix_vector_map[i] = msix_vec;
>   	}
>   	return 0;
>   
> @@ -343,23 +302,18 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
>   	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
>   	int i, err;
>   
> -	vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
> -	if (!vp_dev->vqs)
> -		return -ENOMEM;
> -
>   	err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
>   			dev_name(&vdev->dev), vp_dev);
>   	if (err)
>   		goto out_del_vqs;
>   
>   	vp_dev->intx_enabled = 1;
> -	vp_dev->per_vq_vectors = false;
>   	for (i = 0; i < nvqs; ++i) {
>   		if (!names[i]) {
>   			vqs[i] = NULL;
>   			continue;
>   		}
> -		vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i],
> +		vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i],
>   				VIRTIO_MSI_NO_VECTOR);
>   		if (IS_ERR(vqs[i])) {
>   			err = PTR_ERR(vqs[i]);
> @@ -409,16 +363,15 @@ int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
>   {
>   	struct virtio_device *vdev = vq->vdev;
>   	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> -	struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
> -	struct cpumask *mask;
> -	unsigned int irq;
>   
>   	if (!vq->callback)
>   		return -EINVAL;
>   
>   	if (vp_dev->msix_enabled) {
> -		mask = vp_dev->msix_affinity_masks[info->msix_vector];
> -		irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector);
> +		int vec = vp_dev->msix_vector_map[vq->index];
> +		struct cpumask *mask = vp_dev->msix_affinity_masks[vec];
> +		unsigned int irq = pci_irq_vector(vp_dev->pci_dev, vec);
> +
>   		if (cpu == -1)
>   			irq_set_affinity_hint(irq, NULL);
>   		else {
> @@ -498,8 +451,6 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
>   	vp_dev->vdev.dev.parent = &pci_dev->dev;
>   	vp_dev->vdev.dev.release = virtio_pci_release_dev;
>   	vp_dev->pci_dev = pci_dev;
> -	INIT_LIST_HEAD(&vp_dev->virtqueues);
> -	spin_lock_init(&vp_dev->lock);
>   
>   	/* enable the device */
>   	rc = pci_enable_device(pci_dev);
> diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
> index b2f666250ae0..2038887bdf23 100644
> --- a/drivers/virtio/virtio_pci_common.h
> +++ b/drivers/virtio/virtio_pci_common.h
> @@ -31,17 +31,6 @@
>   #include <linux/highmem.h>
>   #include <linux/spinlock.h>
>   
> -struct virtio_pci_vq_info {
> -	/* the actual virtqueue */
> -	struct virtqueue *vq;
> -
> -	/* the list node for the virtqueues list */
> -	struct list_head node;
> -
> -	/* MSI-X vector (or none) */
> -	unsigned msix_vector;
> -};
> -
>   /* Our device structure */
>   struct virtio_pci_device {
>   	struct virtio_device vdev;
> @@ -75,13 +64,6 @@ struct virtio_pci_device {
>   	/* the IO mapping for the PCI config space */
>   	void __iomem *ioaddr;
>   
> -	/* a list of queues so we can dispatch IRQs */
> -	spinlock_t lock;
> -	struct list_head virtqueues;
> -
> -	/* array of all queues for house-keeping */
> -	struct virtio_pci_vq_info **vqs;
> -
>   	/* MSI-X support */
>   	int msix_enabled;
>   	int intx_enabled;
> @@ -94,16 +76,15 @@ struct virtio_pci_device {
>   	/* Vectors allocated, excluding per-vq vectors if any */
>   	unsigned msix_used_vectors;
>   
> -	/* Whether we have vector per vq */
> -	bool per_vq_vectors;
> +	/* Map of per-VQ MSI-X vectors, may be NULL */
> +	unsigned *msix_vector_map;
>   
>   	struct virtqueue *(*setup_vq)(struct virtio_pci_device *vp_dev,
> -				      struct virtio_pci_vq_info *info,
>   				      unsigned idx,
>   				      void (*callback)(struct virtqueue *vq),
>   				      const char *name,
>   				      u16 msix_vec);
> -	void (*del_vq)(struct virtio_pci_vq_info *info);
> +	void (*del_vq)(struct virtqueue *vq);
>   
>   	u16 (*config_vector)(struct virtio_pci_device *vp_dev, u16 vector);
>   };
> diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
> index 6d9e5173d5fa..47292dad0ff9 100644
> --- a/drivers/virtio/virtio_pci_legacy.c
> +++ b/drivers/virtio/virtio_pci_legacy.c
> @@ -112,7 +112,6 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
>   }
>   
>   static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> -				  struct virtio_pci_vq_info *info,
>   				  unsigned index,
>   				  void (*callback)(struct virtqueue *vq),
>   				  const char *name,
> @@ -130,8 +129,6 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
>   	if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
>   		return ERR_PTR(-ENOENT);
>   
> -	info->msix_vector = msix_vec;
> -
>   	/* create the vring */
>   	vq = vring_create_virtqueue(index, num,
>   				    VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
> @@ -162,9 +159,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
>   	return ERR_PTR(err);
>   }
>   
> -static void del_vq(struct virtio_pci_vq_info *info)
> +static void del_vq(struct virtqueue *vq)
>   {
> -	struct virtqueue *vq = info->vq;
>   	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
>   
>   	iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 4bf7ab375894..00e6fc1df407 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -293,7 +293,6 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
>   }
>   
>   static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> -				  struct virtio_pci_vq_info *info,
>   				  unsigned index,
>   				  void (*callback)(struct virtqueue *vq),
>   				  const char *name,
> @@ -323,8 +322,6 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
>   	/* get offset of notification word for this vq */
>   	off = vp_ioread16(&cfg->queue_notify_off);
>   
> -	info->msix_vector = msix_vec;
> -
>   	/* create the vring */
>   	vq = vring_create_virtqueue(index, num,
>   				    SMP_CACHE_BYTES, &vp_dev->vdev,
> @@ -409,9 +406,8 @@ static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
>   	return 0;
>   }
>   
> -static void del_vq(struct virtio_pci_vq_info *info)
> +static void del_vq(struct virtqueue *vq)
>   {
> -	struct virtqueue *vq = info->vq;
>   	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
>   
>   	vp_iowrite16(vq->index, &vp_dev->common->queue_select);