On 5/19/2015 1:40 AM, Stephen Hemminger wrote:
> +
> +/* set the mapping between vector # and existing eventfd. */
> +static int set_irq_eventfd(struct uio_msi_pci_dev *udev, u32 vec, int fd)
> +{
> + struct uio_msi_irq_ctx *ctx;
> + struct eventfd_ctx *trigger;
> + int irq, err;
> +
> + if (vec >= udev->num_vectors) {
> + dev_notice(&udev->pdev->dev, "vec %u >= num_vec %u\n",
> + vec, udev->num_vectors);
> + return -ERANGE;
> + }
> +
> + irq = udev->msix[vec].vector;
> +
> + /* Clearup existing irq mapping */
> + ctx = &udev->ctx[vec];
> + if (ctx->trigger) {
> + free_irq(irq, ctx->trigger);
> + eventfd_ctx_put(ctx->trigger);
> + ctx->trigger = NULL;
> + }
> +
> + /* Passing -1 is used to disable interrupt */
> + if (fd < 0)
> + return 0;
> +
> +
One unnecessary blank line here.
> + trigger = eventfd_ctx_fdget(fd);
> + if (IS_ERR(trigger)) {
> + err = PTR_ERR(trigger);
> + dev_notice(&udev->pdev->dev,
> + "eventfd ctx get failed: %d\n", err);
> + return err;
> + }
> +
> + err = request_irq(irq, uio_msi_irqhandler, 0, ctx->name, trigger);
> + if (err) {
> + dev_notice(&udev->pdev->dev,
> + "request irq failed: %d\n", err);
> + eventfd_ctx_put(trigger);
> + return err;
> + }
> +
> + dev_dbg(&udev->pdev->dev, "map vector %u to fd %d trigger %p\n",
> + vec, fd, trigger);
> + ctx->trigger = trigger;
> + return 0;
> +}
> +
> +static int
> +uio_msi_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
> +{
> + struct uio_msi_pci_dev *udev
> + = container_of(info, struct uio_msi_pci_dev, info);
> + struct uio_msi_irq_set hdr;
> + int err;
> +
> + switch (cmd) {
> + case UIO_MSI_IRQ_SET:
> + if (copy_from_user(&hdr, (void __user *)arg, sizeof(hdr)))
> + return -EFAULT;
> +
> + mutex_lock(&udev->mutex);
> + err = set_irq_eventfd(udev, hdr.vec, hdr.fd);
> + mutex_unlock(&udev->mutex);
> + break;
> + default:
> + err = -EOPNOTSUPP;
> + }
> + return err;
> +}
"uio_msi_irq_set" defines in single pattern. Compare with the bulk set
in "vfio_irq_set", it requires additional syscall during uio_msix_enable().
> +
> +static int uio_msi_probe(struct pci_dev *pdev, const struct pci_device_id
> *id)
> +{
> + struct uio_msi_pci_dev *udev;
> + int i, err, vectors;
> +
> + udev = kzalloc(sizeof(struct uio_msi_pci_dev), GFP_KERNEL);
> + if (!udev)
> + return -ENOMEM;
> +
> + err = pci_enable_device(pdev);
> + if (err != 0) {
> + dev_err(&pdev->dev, "cannot enable PCI device\n");
> + goto fail_free;
> + }
> +
> + vectors = pci_msix_vec_count(pdev);
> + if (vectors < 0) {
> + dev_err(&pdev->dev, "device does not support MSI-X\n");
> + err = -EINVAL;
> + goto fail_disable;
> + }
pci_msix_vec_count() is available since v3.14, it requires a compatible
check.
In order to support older version, probably a function
'uio_msix_vec_count()' is necessary.
I've one overall question, is there a special reason not enhance igb_uio
but define a new uio_msi? And the looks like the piece could be add
into igb_uio or uio_pci_generic as well. Do you have plan for the
latter? Thanks.
