3.5.7.31 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Yijing Wang <wangyijing@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
[ luis: backported to 3.5: used Yijing Wang's backport to 3.4 ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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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