Messages in this thread Patch in this message | | | From | Luis Henriques <> | Subject | [PATCH 3.5 01/60] PCI: Enable ARI if dev and upstream bridge support it; disable otherwise | Date | Fri, 21 Feb 2014 13:00:28 +0000 |
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3.5.7.31 -stable review patch. If anyone has any objections, please let me know.
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From: Yijing Wang <wangyijing@huawei.com>
commit b0cc6020e1cc62f1253215f189611b34be4a83c7 upstream.
Currently, we enable ARI in a device's upstream bridge if the bridge and the device support it. But we never disable ARI, even if the device is removed and replaced with a device that doesn't support ARI.
This means that if we hot-remove an ARI device and replace it with a non-ARI multi-function device, we find only function 0 of the new device because the upstream bridge still has ARI enabled, and next_ari_fn() only returns function 0 for the new non-ARI device.
This patch disables ARI in the upstream bridge if the device doesn't support ARI. See the PCIe spec, r3.0, sec 6.13.
[bhelgaas: changelog, function comment] Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> [ luis: backported to 3.5: used Yijing Wang's backport to 3.4 ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/pci/pci.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index fa7c0f0..caeddd4 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1974,6 +1974,9 @@ void pci_free_cap_save_buffers(struct pci_dev *dev) /** * pci_enable_ari - enable ARI forwarding if hardware support it * @dev: the PCI device + * + * If @dev and its upstream bridge both support ARI, enable ARI in the + * bridge. Otherwise, disable ARI in the bridge. */ void pci_enable_ari(struct pci_dev *dev) { @@ -1985,10 +1988,6 @@ void pci_enable_ari(struct pci_dev *dev) if (pcie_ari_disabled || !pci_is_pcie(dev) || dev->devfn) return; - pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI); - if (!pos) - return; - bridge = dev->bus->self; if (!bridge || !pci_is_pcie(bridge)) return; @@ -2007,10 +2006,14 @@ void pci_enable_ari(struct pci_dev *dev) return; pci_read_config_word(bridge, pos + PCI_EXP_DEVCTL2, &ctrl); - ctrl |= PCI_EXP_DEVCTL2_ARI; + if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI)) { + ctrl |= PCI_EXP_DEVCTL2_ARI; + bridge->ari_enabled = 1; + } else { + ctrl &= ~PCI_EXP_DEVCTL2_ARI; + bridge->ari_enabled = 0; + } pci_write_config_word(bridge, pos + PCI_EXP_DEVCTL2, ctrl); - - bridge->ari_enabled = 1; } /** -- 1.9.0
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