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virtio_pci: minor MSI-X cleanups
1) Rename vp_request_vectors to vp_request_msix_vectors, and take non-MSI-X case out to caller. 2) Comment weird pci_enable_msix API 3) Rename vp_find_vq to setup_vq. 4) Fix spaces to tabs 5) Make nvectors calc internal to vp_try_to_find_vqs() 6) Rename vector to msix_vector for more clarity. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com>
This commit is contained in:
Rusty Russell
parent
ebc79c4f8d
commit
f68d24082e
1 changed files with 70 additions and 55 deletions
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@ -84,7 +84,7 @@ struct virtio_pci_vq_info
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struct list_head node;
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/* MSI-X vector (or none) */
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unsigned vector;
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unsigned msix_vector;
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};
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/* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
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@ -280,25 +280,14 @@ static void vp_free_vectors(struct virtio_device *vdev)
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vp_dev->msix_entries = NULL;
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}
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static int vp_request_vectors(struct virtio_device *vdev, int nvectors,
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bool per_vq_vectors)
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static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
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bool per_vq_vectors)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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const char *name = dev_name(&vp_dev->vdev.dev);
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unsigned i, v;
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int err = -ENOMEM;
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if (!nvectors) {
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/* Can't allocate MSI-X vectors, use regular interrupt */
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vp_dev->msix_vectors = 0;
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err = request_irq(vp_dev->pci_dev->irq, vp_interrupt,
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IRQF_SHARED, name, vp_dev);
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if (err)
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return err;
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vp_dev->intx_enabled = 1;
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return 0;
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}
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vp_dev->msix_entries = kmalloc(nvectors * sizeof *vp_dev->msix_entries,
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GFP_KERNEL);
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if (!vp_dev->msix_entries)
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@ -311,6 +300,7 @@ static int vp_request_vectors(struct virtio_device *vdev, int nvectors,
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for (i = 0; i < nvectors; ++i)
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vp_dev->msix_entries[i].entry = i;
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/* pci_enable_msix returns positive if we can't get this many. */
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err = pci_enable_msix(vp_dev->pci_dev, vp_dev->msix_entries, nvectors);
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if (err > 0)
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err = -ENOSPC;
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@ -356,10 +346,22 @@ error:
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return err;
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}
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static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
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void (*callback)(struct virtqueue *vq),
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const char *name,
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u16 vector)
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static int vp_request_intx(struct virtio_device *vdev)
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{
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int err;
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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err = request_irq(vp_dev->pci_dev->irq, vp_interrupt,
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IRQF_SHARED, dev_name(&vdev->dev), vp_dev);
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if (!err)
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vp_dev->intx_enabled = 1;
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return err;
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}
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static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index,
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void (*callback)(struct virtqueue *vq),
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const char *name,
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u16 msix_vec)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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struct virtio_pci_vq_info *info;
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@ -384,7 +386,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
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info->queue_index = index;
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info->num = num;
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info->vector = vector;
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info->msix_vector = msix_vec;
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size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
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info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
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@ -408,10 +410,10 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
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vq->priv = info;
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info->vq = vq;
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if (vector != VIRTIO_MSI_NO_VECTOR) {
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iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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vector = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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if (vector == VIRTIO_MSI_NO_VECTOR) {
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if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
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iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
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err = -EBUSY;
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goto out_assign;
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}
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@ -472,7 +474,8 @@ static void vp_del_vqs(struct virtio_device *vdev)
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list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
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info = vq->priv;
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if (vp_dev->per_vq_vectors)
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free_irq(vp_dev->msix_entries[info->vector].vector, vq);
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free_irq(vp_dev->msix_entries[info->msix_vector].vector,
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vq);
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vp_del_vq(vq);
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}
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vp_dev->per_vq_vectors = false;
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@ -484,38 +487,58 @@ static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs,
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struct virtqueue *vqs[],
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vq_callback_t *callbacks[],
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const char *names[],
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int nvectors,
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bool use_msix,
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bool per_vq_vectors)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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u16 vector;
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int i, err, allocated_vectors;
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u16 msix_vec;
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int i, err, nvectors, allocated_vectors;
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err = vp_request_vectors(vdev, nvectors, per_vq_vectors);
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if (err)
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goto error_request;
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if (!use_msix) {
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/* Old style: one normal interrupt for change and all vqs. */
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err = vp_request_intx(vdev);
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if (err)
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goto error_request;
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} else {
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if (per_vq_vectors) {
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/* Best option: one for change interrupt, one per vq. */
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nvectors = 1;
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for (i = 0; i < nvqs; ++i)
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if (callbacks[i])
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++nvectors;
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} else {
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/* Second best: one for change, shared for all vqs. */
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nvectors = 2;
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}
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err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors);
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if (err)
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goto error_request;
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}
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vp_dev->per_vq_vectors = per_vq_vectors;
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allocated_vectors = vp_dev->msix_used_vectors;
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for (i = 0; i < nvqs; ++i) {
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if (!callbacks[i] || !vp_dev->msix_enabled)
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vector = VIRTIO_MSI_NO_VECTOR;
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msix_vec = VIRTIO_MSI_NO_VECTOR;
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else if (vp_dev->per_vq_vectors)
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vector = allocated_vectors++;
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msix_vec = allocated_vectors++;
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else
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vector = VP_MSIX_VQ_VECTOR;
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vqs[i] = vp_find_vq(vdev, i, callbacks[i], names[i], vector);
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msix_vec = VP_MSIX_VQ_VECTOR;
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vqs[i] = setup_vq(vdev, i, callbacks[i], names[i], msix_vec);
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if (IS_ERR(vqs[i])) {
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err = PTR_ERR(vqs[i]);
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goto error_find;
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}
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/* allocate per-vq irq if available and necessary */
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if (vp_dev->per_vq_vectors && vector != VIRTIO_MSI_NO_VECTOR) {
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snprintf(vp_dev->msix_names[vector], sizeof *vp_dev->msix_names,
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"%s-%s", dev_name(&vp_dev->vdev.dev), names[i]);
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err = request_irq(vp_dev->msix_entries[vector].vector,
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vring_interrupt, 0,
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vp_dev->msix_names[vector], vqs[i]);
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if (vp_dev->per_vq_vectors) {
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snprintf(vp_dev->msix_names[msix_vec],
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sizeof *vp_dev->msix_names,
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"%s-%s",
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dev_name(&vp_dev->vdev.dev), names[i]);
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err = request_irq(msix_vec, vring_interrupt, 0,
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vp_dev->msix_names[msix_vec],
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vqs[i]);
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if (err) {
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vp_del_vq(vqs[i]);
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goto error_find;
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@ -537,28 +560,20 @@ static int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
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vq_callback_t *callbacks[],
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const char *names[])
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{
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int vectors = 0;
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int i, uninitialized_var(err);
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int err;
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/* How many vectors would we like? */
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for (i = 0; i < nvqs; ++i)
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if (callbacks[i])
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++vectors;
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/* We want at most one vector per queue and one for config changes. */
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err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
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vectors + 1, true);
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/* Try MSI-X with one vector per queue. */
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err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, true, true);
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if (!err)
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return 0;
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/* Fallback to separate vectors for config and a shared for queues. */
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/* Fallback: MSI-X with one vector for config, one shared for queues. */
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err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
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2, false);
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true, false);
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if (!err)
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return 0;
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/* Finally fall back to regular interrupts. */
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err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
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0, false);
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return err;
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return vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
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false, false);
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}
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static struct virtio_config_ops virtio_pci_config_ops = {
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