On Fri, 2012-09-21 at 16:43 +0800, Yijing Wang wrote:
> When we injected aer errors to the pcie device by aer_inject module, pci_ops of the pci
> bus the device on will be assigned to pci_ops_aer.So if the target pci device
> is a bridge, once we hot-remove and hot-add the bridge, the newly created child bus's pci_ops
> will be assigned to pci_ops_aer too.Now every access to the child bus's device will cause the
> system panic, because it will get a NULL pci_ops in pci_read_aer/pci_write_aer.
>
> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
> Reviewed-by: Sven Dietrich <Sven.Dietrich@xxxxxxxxxx>
Reviewed-by: Huang Ying <ying.huang@xxxxxxxxx>
> ---
> drivers/pci/pcie/aer/aer_inject.c | 26 +++++++++++++++++++++++++-
> 1 files changed, 25 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c
> index 4e24cb8..fdab3bb 100644
> --- a/drivers/pci/pcie/aer/aer_inject.c
> +++ b/drivers/pci/pcie/aer/aer_inject.c
> @@ -109,6 +109,26 @@ static struct aer_error *__find_aer_error_by_dev(struct pci_dev *dev)
> return __find_aer_error((u16)domain, dev->bus->number, dev->devfn);
> }
>
> +/* find pci_ops of the nearest parent bus */
> +static struct pci_ops *__find_pci_bus_ops_parent(struct pci_bus *bus)
> +{
> + struct pci_bus_ops *bus_ops;
> + struct pci_bus *pbus = bus->parent;
> +
> + if (!pbus)
> + return NULL;
> +
> + while (pbus) {
> + list_for_each_entry(bus_ops, &pci_bus_ops_list, list)
> + if (bus_ops->bus == pbus)
> + return bus_ops->ops;
> +
> + pbus = pbus->parent;
> + }
> +
> + return NULL;
> +}
> +
> /* inject_lock must be held before calling */
> static struct pci_ops *__find_pci_bus_ops(struct pci_bus *bus)
> {
> @@ -118,7 +138,9 @@ static struct pci_ops *__find_pci_bus_ops(struct pci_bus *bus)
> if (bus_ops->bus == bus)
> return bus_ops->ops;
> }
> - return NULL;
> +
> + /* can't find bus_ops, fall back to get bus_ops of parent bus */
> + return __find_pci_bus_ops_parent(bus);
> }
>
> static struct pci_bus_ops *pci_bus_ops_pop(void)
> @@ -208,6 +230,7 @@ static int pci_read_aer(struct pci_bus *bus, unsigned int devfn, int where,
> }
> out:
> ops = __find_pci_bus_ops(bus);
> + BUG_ON(!ops);
> spin_unlock_irqrestore(&inject_lock, flags);
> return ops->read(bus, devfn, where, size, val);
> }
> @@ -243,6 +266,7 @@ int pci_write_aer(struct pci_bus *bus, unsigned int devfn, int where, int size,
> }
> out:
> ops = __find_pci_bus_ops(bus);
> + BUG_ON(!ops);
> spin_unlock_irqrestore(&inject_lock, flags);
> return ops->write(bus, devfn, where, size, val);
> }
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