Commit faa48a50 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

PCI: Remove spurious error for sriov_numvfs store and simplify flow 



If we request "num_vfs" and the driver's sriov_configure() method enables
exactly that number ("num_vfs_enabled"), we complain "Invalid value for
number of VFs to enable" and return an error.  We should silently return
success instead.

Also, use kstrtou16() since numVFs is defined to be a 16-bit field and
rework to simplify control flow.

Reported-by: default avatarGreg Rose <gregory.v.rose@intel.com>
Reference: http://lkml.kernel.org/r/20121214101911.00002f59@unknown


Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Tested-by: default avatarDonald Dutile <ddutile@redhat.com>
parent a49f0d1e

drivers/pci/pci-sysfs.c

+34 −51
Original line number Diff line number Diff line
@@ -422,77 +422,60 @@ static ssize_t sriov_numvfs_show(struct device *dev, 
}



/*

 * num_vfs > 0; number of vfs to enable

 * num_vfs = 0; disable all vfs

 * num_vfs > 0; number of VFs to enable

 * num_vfs = 0; disable all VFs

 *

 * Note: SRIOV spec doesn't allow partial VF

 *       disable, so its all or none.

 *       disable, so it's all or none.

 */

static ssize_t sriov_numvfs_store(struct device *dev,

				  struct device_attribute *attr,

				  const char *buf, size_t count)

{

	struct pci_dev *pdev = to_pci_dev(dev);

	int num_vfs_enabled = 0;

	int num_vfs;

	int ret = 0;

	u16 total;

	int ret;

	u16 num_vfs;



	if (kstrtoint(buf, 0, &num_vfs) < 0)

		return -EINVAL;

	ret = kstrtou16(buf, 0, &num_vfs);

	if (ret < 0)

		return ret;



	if (num_vfs > pci_sriov_get_totalvfs(pdev))

		return -ERANGE;



	if (num_vfs == pdev->sriov->num_VFs)

		return count;		/* no change */



	/* is PF driver loaded w/callback */

	if (!pdev->driver || !pdev->driver->sriov_configure) {

		dev_info(&pdev->dev,

			 "Driver doesn't support SRIOV configuration via sysfs\n");

		dev_info(&pdev->dev, "Driver doesn't support SRIOV configuration via sysfs\n");

		return -ENOSYS;

	}



	/* if enabling vf's ... */

	total = pci_sriov_get_totalvfs(pdev);

	/* Requested VFs to enable < totalvfs and none enabled already */

	if ((num_vfs > 0) && (num_vfs <= total)) {

		if (pdev->sriov->num_VFs == 0) {

			num_vfs_enabled =

				pdev->driver->sriov_configure(pdev, num_vfs);

			if ((num_vfs_enabled >= 0) &&

			    (num_vfs_enabled != num_vfs)) {

				dev_warn(&pdev->dev,

					 "Only %d VFs enabled\n",

					 num_vfs_enabled);

				return count;

			} else if (num_vfs_enabled < 0)

				/* error code from driver callback */

				return num_vfs_enabled;

		} else if (num_vfs == pdev->sriov->num_VFs) {

			dev_warn(&pdev->dev,

				 "%d VFs already enabled; no enable action taken\n",

				 num_vfs);

			return count;

		} else {

			dev_warn(&pdev->dev,

				 "%d VFs already enabled. Disable before enabling %d VFs\n",

				 pdev->sriov->num_VFs, num_vfs);

			return -EINVAL;

		}

	}



	/* disable vfs */

	if (num_vfs == 0) {

		if (pdev->sriov->num_VFs != 0) {

		/* disable VFs */

		ret = pdev->driver->sriov_configure(pdev, 0);

			return ret ? ret : count;

		} else {

			dev_warn(&pdev->dev,

				 "All VFs disabled; no disable action taken\n");

		if (ret < 0)

			return ret;

		return count;

	}



	/* enable VFs */

	if (pdev->sriov->num_VFs) {

		dev_warn(&pdev->dev, "%d VFs already enabled. Disable before enabling %d VFs\n",

			 pdev->sriov->num_VFs, num_vfs);

		return -EBUSY;

	}



	dev_err(&pdev->dev,

		"Invalid value for number of VFs to enable: %d\n", num_vfs);

	ret = pdev->driver->sriov_configure(pdev, num_vfs);

	if (ret < 0)

		return ret;



	return -EINVAL;

	if (ret != num_vfs)

		dev_warn(&pdev->dev, "%d VFs requested; only %d enabled\n",

			 num_vfs, ret);



	return count;

}



static struct device_attribute sriov_totalvfs_attr = __ATTR_RO(sriov_totalvfs);

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