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: 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>
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 8f1e117..5fffca9 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -51,24 +51,16 @@
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 @@
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 @@
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 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 @@
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 @@
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;
}