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

Jason Wang
2017-02-08T02:54:32Z

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@lst.de>
> 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@lst.de>

Reviewed-by: Jason Wang <jasowang@redhat.com>

> ---
> 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);