From dc087f2f6a2925e81831f3016b9cbb6e470e7423 Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Sat, 25 May 2013 21:48:37 +0800 Subject: [PATCH] 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 Signed-off-by: Bjorn Helgaas Cc: Donald Dutile Cc: Yinghai Lu Cc: Ram Pai --- drivers/pci/iov.c | 59 +++++++++++++++++++---------------------------- 1 file changed, 24 insertions(+), 35 deletions(-) diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 8f1e1174b71f..5fffca995a91 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -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; } -- 2.39.5