On Tue, 25 Aug 2009 09:34:34 pm Michael S. Tsirkin wrote:
> > That's because we didn't do the request_irq's for the per_vector case,
> > because
> > we don't have the names. This is what prevented me from doing a nice
> > encapsulation.
>
> Yes. But let's split free_vectors out into free_msix_vectors and
> free_intx as well?
Perhaps. Patch welcome :)
> Yes, I agree, this is good cleanup, structure field names should be
> desriptive. Are you sure we want to make all local variables named
> vector renamed to msix_vector though? CodingStyle says local var names
> should be short ... A couple of ideas below.
msix_vec would work. But vector for something which isn't always the vector
is misleading, IMHO.
> > - if (vector != VIRTIO_MSI_NO_VECTOR) {
> > - iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
> > - vector = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
> > - if (vector == VIRTIO_MSI_NO_VECTOR) {
> > + if (msix_vector != VIRTIO_MSI_NO_VECTOR) {
> > + iowrite16(msix_vector, vp_dev->ioaddr+VIRTIO_MSI_QUEUE_VECTOR);
> > + msix_vector = ioread16(vp_dev->ioaddr+VIRTIO_MSI_QUEUE_VECTOR);
>
> checkpatch will complain that space is lacking around "+".
> We won't have a problem if we keep it named vector.
Yeah, but OTOH ignoring checkpatch warnings is good for the soul.
> > if (!use_msix) {
> > /* Old style: one normal interrupt for change and all vqs. */
> > vp_dev->msix_vectors = 0;
> > - vp_dev->per_vq_vectors = false;
>
> I know it's enough to look at msix_vectors, but isn't
> it cleaner to have per_vq_vectors consistent as well?
> E.g. del_vqs seems to only look at per_vq_vectors.
This should in fact be:
if (!use_msix) {
/* Old style: one normal interrupt for change and all vqs. */
- vp_dev->msix_vectors = 0;
- vp_dev->per_vq_vectors = false;
err = request_irq(vp_dev->pci_dev->irq, vp_interrupt,
IRQF_SHARED, dev_name(&vdev->dev), vp_dev);
- if (!err)
- vp_dev->intx_enabled = 1;
- return err;
+ if (err)
+ return err;
+ vp_dev->intx_enabled = 1;
The msix fields should all be ignored if msix_enabled is false. Think about
running valgrind (or equiv) over the code: if you initialize something which
shouldn't be accessed, valgrind won't spot it.
For similar reasons, I dislike memseting structs to 0, or kzallocing them.
> > err = request_irq(vp_dev->pci_dev->irq, vp_interrupt,
> > IRQF_SHARED, dev_name(&vdev->dev), vp_dev);
> > - if (!err)
> > - vp_dev->intx_enabled = 1;
> > - return err;
> > + if (err)
> > + return err;
>
> Maybe move this part out into a separate function? This way
> vp_try_to_find_vqs does high-level processing.
Nice. Moved this to vp_request_intx().
> > + } else {
> > + if (per_vq_vectors) {
> > + /* Best option: one for change interrupt, one per vq. */
> > + nvectors = 1;
> > + for (i = 0; i < nvqs; ++i)
> > + if (callbacks[i])
> > + ++nvectors;
> > + } else {
> > + /* Second best: one for change, shared for all vqs. */
> > + nvectors = 2;
>
> Out of curiosity: why do you put {} here? They aren't
> strictly necessary ...
Comment made it multiline, looked a bit neater?
Here's the diff result:
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
@@ -346,10 +346,22 @@ error:
return err;
}
+static int vp_request_intx(struct virtio_device *vdev)
+{
+ int err;
+ struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+ err = request_irq(vp_dev->pci_dev->irq, vp_interrupt,
+ IRQF_SHARED, dev_name(&vdev->dev), vp_dev);
+ if (!err)
+ vp_dev->intx_enabled = 1;
+ return err;
+}
+
static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name,
- u16 msix_vector)
+ u16 msix_vec)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
struct virtio_pci_vq_info *info;
@@ -374,7 +386,7 @@ static struct virtqueue *setup_vq(struct
info->queue_index = index;
info->num = num;
- info->msix_vector = msix_vector;
+ info->msix_vector = msix_vec;
size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
@@ -398,10 +410,10 @@ static struct virtqueue *setup_vq(struct
vq->priv = info;
info->vq = vq;
- if (msix_vector != VIRTIO_MSI_NO_VECTOR) {
- iowrite16(msix_vector, vp_dev->ioaddr+VIRTIO_MSI_QUEUE_VECTOR);
- msix_vector = ioread16(vp_dev->ioaddr+VIRTIO_MSI_QUEUE_VECTOR);
- if (msix_vector == VIRTIO_MSI_NO_VECTOR) {
+ if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
+ iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
+ msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
+ if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
err = -EBUSY;
goto out_assign;
}
@@ -479,16 +491,14 @@ static int vp_try_to_find_vqs(struct vir
bool per_vq_vectors)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
- u16 msix_vector;
+ u16 msix_vec;
int i, err, nvectors, allocated_vectors;
if (!use_msix) {
/* Old style: one normal interrupt for change and all vqs. */
- err = request_irq(vp_dev->pci_dev->irq, vp_interrupt,
- IRQF_SHARED, dev_name(&vdev->dev), vp_dev);
+ err = vp_request_intx(vdev);
if (err)
- return err;
- vp_dev->intx_enabled = 1;
+ goto error_request;
} else {
if (per_vq_vectors) {
/* Best option: one for change interrupt, one per vq. */
@@ -510,24 +520,24 @@ static int vp_try_to_find_vqs(struct vir
allocated_vectors = vp_dev->msix_used_vectors;
for (i = 0; i < nvqs; ++i) {
if (!callbacks[i] || !vp_dev->msix_enabled)
- msix_vector = VIRTIO_MSI_NO_VECTOR;
+ msix_vec = VIRTIO_MSI_NO_VECTOR;
else if (vp_dev->per_vq_vectors)
- msix_vector = allocated_vectors++;
+ msix_vec = allocated_vectors++;
else
- msix_vector = VP_MSIX_VQ_VECTOR;
- vqs[i] = setup_vq(vdev, i, callbacks[i], names[i], msix_vector);
+ msix_vec = VP_MSIX_VQ_VECTOR;
+ vqs[i] = setup_vq(vdev, i, callbacks[i], names[i], msix_vec);
if (IS_ERR(vqs[i])) {
err = PTR_ERR(vqs[i]);
goto error_find;
}
/* allocate per-vq irq if available and necessary */
if (vp_dev->per_vq_vectors) {
- snprintf(vp_dev->msix_names[msix_vector],
+ snprintf(vp_dev->msix_names[msix_vec],
sizeof *vp_dev->msix_names,
"%s-%s",
dev_name(&vp_dev->vdev.dev), names[i]);
- err = request_irq(msix_vector, vring_interrupt, 0,
- vp_dev->msix_names[msix_vector],
+ err = request_irq(msix_vec, vring_interrupt, 0,
+ vp_dev->msix_names[msix_vec],
vqs[i]);
if (err) {
vp_del_vq(vqs[i]);
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