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PCI: Simplify IOV implementation and fix reference count races

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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: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ram Pai <linuxram@us.ibm.com>
This commit is contained in:
Jiang Liu 2013-05-25 21:48:37 +08:00 committed by Bjorn Helgaas
parent d35329d9f1
commit dc087f2f6a
1 changed files with 24 additions and 35 deletions
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59
drivers/pci/iov.c
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@ -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 @@ failed1:
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 @@ failed1:
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;
pci_dev_put(pdev);
if (!pdev->is_physfn)
if (!pdev->is_physfn) {
pci_dev_put(pdev);
return -ENODEV;
}
rc = sysfs_create_link(&dev->dev.kobj,
&pdev->dev.kobj, "dep_link");
pci_dev_put(pdev);
if (rc)
return rc;
}