DPDK patches and discussions
 help / color / mirror / Atom feed
From: "Liang, Cunming" <cunming.liang@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>,  cumming.lian@intel.com
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 4/5] uio: new driver with MSI-X support
Date: Mon, 25 May 2015 14:01:14 +0800	[thread overview]
Message-ID: <5562BAAA.5050301@intel.com> (raw)
In-Reply-To: <1431970814-25951-5-git-send-email-stephen@networkplumber.org>



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.

  reply	other threads:[~2015-05-25  6:01 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-18 17:40 [dpdk-dev] [PATCH 0/5] receive IRQ related patches Stephen Hemminger
2015-05-18 17:40 ` [dpdk-dev] [PATCH 1/5] ethdev: check for rxq interrupt support Stephen Hemminger
2015-05-18 17:40 ` [dpdk-dev] [PATCH 2/5] ethdev: remove unnecessary checks Stephen Hemminger
2015-05-18 17:40 ` [dpdk-dev] [PATCH 3/5] ethdev: fix errors if RTE_ETHDEV_DEBUG enabled Stephen Hemminger
2015-05-18 17:40 ` [dpdk-dev] [PATCH 4/5] uio: new driver with MSI-X support Stephen Hemminger
2015-05-25  6:01   ` Liang, Cunming [this message]
2015-05-25 17:41     ` Stephen Hemminger
2015-05-18 17:40 ` [dpdk-dev] [PATCH 5/5] uio: integrate " Stephen Hemminger
2015-05-25  8:55   ` Liang, Cunming
2015-05-25 17:42     ` Stephen Hemminger
2015-07-09  0:28 ` [dpdk-dev] [PATCH 0/5] receive IRQ related patches Thomas Monjalon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=5562BAAA.5050301@intel.com \
    --to=cunming.liang@intel.com \
    --cc=cumming.lian@intel.com \
    --cc=dev@dpdk.org \
    --cc=stephen@networkplumber.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).