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Commit dc087f2f authored by Jiang Liu's avatar Jiang Liu Committed by Bjorn Helgaas
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PCI: Simplify IOV implementation and fix reference count races 



Trivial changes to IOV:

  1) use new PCI interfaces to simplify IOV implementation
  2) fix some reference count related race windows

[bhelgaas: fix virtfn_add() add bus/alloc dev error paths]
Signed-off-by: default avatarJiang Liu <jiang.liu@huawei.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ram Pai <linuxram@us.ibm.com>
parent d35329d9

drivers/pci/iov.c

+24 −35
Original line number Diff line number Diff line
@@ -51,24 +51,16 @@ static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr) 
	return child;

}



static void virtfn_remove_bus(struct pci_bus *bus, int busnr)

static void virtfn_remove_bus(struct pci_bus *physbus, struct pci_bus *virtbus)

{

	struct pci_bus *child;



	if (bus->number == busnr)

		return;



	child = pci_find_bus(pci_domain_nr(bus), busnr);

	BUG_ON(!child);



	if (list_empty(&child->devices))

		pci_remove_bus(child);

	if (physbus != virtbus && list_empty(&virtbus->devices))

		pci_remove_bus(virtbus);

}



static int virtfn_add(struct pci_dev *dev, int id, int reset)

{

	int i;

	int rc;

	int rc = -ENOMEM;

	u64 size;

	char buf[VIRTFN_ID_LEN];

	struct pci_dev *virtfn;
@@ -76,18 +68,15 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset) 
	struct pci_sriov *iov = dev->sriov;

	struct pci_bus *bus;



	virtfn = pci_alloc_dev(NULL);

	if (!virtfn)

		return -ENOMEM;



	mutex_lock(&iov->dev->sriov->lock);

	bus = virtfn_add_bus(dev->bus, virtfn_bus(dev, id));

	if (!bus) {

		kfree(virtfn);

		mutex_unlock(&iov->dev->sriov->lock);

		return -ENOMEM;

	}

	virtfn->bus = pci_bus_get(bus);

	if (!bus)

		goto failed;



	virtfn = pci_alloc_dev(bus);

	if (!virtfn)

		goto failed0;



	virtfn->devfn = virtfn_devfn(dev, id);

	virtfn->vendor = dev->vendor;

	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
@@ -136,7 +125,9 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset) 
	pci_dev_put(dev);

	mutex_lock(&iov->dev->sriov->lock);

	pci_stop_and_remove_bus_device(virtfn);

	virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));

failed0:

	virtfn_remove_bus(dev->bus, bus);

failed:

	mutex_unlock(&iov->dev->sriov->lock);



	return rc;
@@ -145,20 +136,15 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset) 
static void virtfn_remove(struct pci_dev *dev, int id, int reset)

{

	char buf[VIRTFN_ID_LEN];

	struct pci_bus *bus;

	struct pci_dev *virtfn;

	struct pci_sriov *iov = dev->sriov;



	bus = pci_find_bus(pci_domain_nr(dev->bus), virtfn_bus(dev, id));

	if (!bus)

		return;



	virtfn = pci_get_slot(bus, virtfn_devfn(dev, id));

	virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),

					     virtfn_bus(dev, id),

					     virtfn_devfn(dev, id));

	if (!virtfn)

		return;



	pci_dev_put(virtfn);



	if (reset) {

		device_release_driver(&virtfn->dev);

		__pci_reset_function(virtfn);
@@ -176,9 +162,11 @@ static void virtfn_remove(struct pci_dev *dev, int id, int reset) 


	mutex_lock(&iov->dev->sriov->lock);

	pci_stop_and_remove_bus_device(virtfn);

	virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));

	virtfn_remove_bus(dev->bus, virtfn->bus);

	mutex_unlock(&iov->dev->sriov->lock);



	/* balance pci_get_domain_bus_and_slot() */

	pci_dev_put(virtfn);

	pci_dev_put(dev);

}
@@ -335,13 +323,14 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn) 
		if (!pdev)

			return -ENODEV;



		if (!pdev->is_physfn) {

			pci_dev_put(pdev);



		if (!pdev->is_physfn)

			return -ENODEV;

		}



		rc = sysfs_create_link(&dev->dev.kobj,

					&pdev->dev.kobj, "dep_link");

		pci_dev_put(pdev);

		if (rc)

			return rc;

	}