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Message-ID: <CAE9FiQX-3=U7YpEnRsL46Kn0Dyvk_+A1NC7UYijHe91KWjrKDA@mail.gmail.com>
Date: Mon, 27 May 2013 19:00:26 -0700
From: Yinghai Lu <yinghai@...nel.org>
To: Jiang Liu <liuj97@...il.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
Jiang Liu <jiang.liu@...wei.com>,
"Rafael J . Wysocki" <rjw@...k.pl>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Gu Zheng <guz.fnst@...fujitsu.com>,
Toshi Kani <toshi.kani@...com>,
Myron Stowe <myron.stowe@...hat.com>,
Yijing Wang <wangyijing@...wei.com>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Donald Dutile <ddutile@...hat.com>,
Ram Pai <linuxram@...ibm.com>
Subject: Re: [PATCH v3, part1 09/10] PCI, IOV: simplify IOV implementation
On Sat, May 25, 2013 at 6:48 AM, Jiang Liu <liuj97@...il.com> wrote:
> Trivial changes to IOV:
> 1) use new PCI interfaces to simplify IOV implementation
> 2) fix some reference count related race windows
>
> Signed-off-by: Jiang Liu <jiang.liu@...wei.com>
> Cc: Donald Dutile <ddutile@...hat.com>
> Cc: Yinghai Lu <yinghai@...nel.org>
> Cc: Ram Pai <linuxram@...ibm.com>
> Cc: linux-pci@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> ---
> drivers/pci/iov.c | 58 +++++++++++++++++++++----------------------------------
> 1 file changed, 22 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index 8f1e117..3e33499 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -51,43 +51,30 @@ 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;
> + struct pci_dev *virtfn = NULL;
> struct resource *res;
> 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)
> + 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 +123,8 @@ 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));
> + virtfn_remove_bus(dev->bus, bus);
> +failed0:
need to swap above two lines. otherwise virtual bus could not be removed.
> mutex_unlock(&iov->dev->sriov->lock);
>
> return rc;
> @@ -145,20 +133,15 @@ 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 +159,11 @@ 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 +320,14 @@ 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;
> }
> --
> 1.8.1.2
>
--
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