| Message ID | 1437601197-6481-11-git-send-email-wdavis@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Wed, Jul 22, 2015 at 04:39:55PM -0500, Will Davis wrote: > Adds an interface to find the first device which is upstream of both > devices. > > Signed-off-by: Will Davis <wdavis@nvidia.com> > --- > drivers/pci/search.c | 25 +++++++++++++++++++++++++ > include/linux/pci.h | 2 ++ > 2 files changed, 27 insertions(+) > > diff --git a/drivers/pci/search.c b/drivers/pci/search.c > index a20ce7d..cbd8163 100644 > --- a/drivers/pci/search.c > +++ b/drivers/pci/search.c > @@ -384,3 +384,28 @@ int pci_dev_present(const struct pci_device_id *ids) > return 0; > } > EXPORT_SYMBOL(pci_dev_present); > + > +/** > + * pci_find_common_upstream_dev - Returns the first common upstream device > + * @from: the PCI device to search for a common upstream device from > + * @to: the PCI device to search for a common upstream device to > + * > + * Walks up the bus hierarchy from the @from device, looking for the first bus > + * which the @to device is downstream of. Returns %NULL if the devices do not > + * share any upstream devices. This interface looks like it should be symmetric: you should get the same answer regardless of which device is "from" and which is "to". I would rename the arguments to something more neutral to reflect that. > + */ > +struct pci_dev *pci_find_common_upstream_dev(struct pci_dev *from, > + struct pci_dev *to) > +{ > + struct pci_dev *pdev = from; > + > + while (pdev != NULL) { > + if ((to->bus->number >= pdev->bus->busn_res.start) && > + (to->bus->number <= pdev->bus->busn_res.end)) > + return pdev; > + pdev = pdev->bus->self; I think you want "pdev = pci_upstream_bridge(pdev)" here; otherwise you'll exit the loop early if "from" is a VF on a virtual bus. > + } > + > + return NULL; > +} > +EXPORT_SYMBOL(pci_find_common_upstream_dev); > diff --git a/include/linux/pci.h b/include/linux/pci.h > index d58063e..8262b9e 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -860,6 +860,8 @@ static inline struct pci_dev *pci_get_bus_and_slot(unsigned int bus, > } > struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from); > int pci_dev_present(const struct pci_device_id *ids); > +struct pci_dev *pci_find_common_upstream_dev(struct pci_dev *from, > + struct pci_dev *to); > > int pci_bus_read_config_byte(struct pci_bus *bus, unsigned int devfn, > int where, u8 *val); > -- > 2.4.6 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/search.c b/drivers/pci/search.c index a20ce7d..cbd8163 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -384,3 +384,28 @@ int pci_dev_present(const struct pci_device_id *ids) return 0; } EXPORT_SYMBOL(pci_dev_present); + +/** + * pci_find_common_upstream_dev - Returns the first common upstream device + * @from: the PCI device to search for a common upstream device from + * @to: the PCI device to search for a common upstream device to + * + * Walks up the bus hierarchy from the @from device, looking for the first bus + * which the @to device is downstream of. Returns %NULL if the devices do not + * share any upstream devices. + */ +struct pci_dev *pci_find_common_upstream_dev(struct pci_dev *from, + struct pci_dev *to) +{ + struct pci_dev *pdev = from; + + while (pdev != NULL) { + if ((to->bus->number >= pdev->bus->busn_res.start) && + (to->bus->number <= pdev->bus->busn_res.end)) + return pdev; + pdev = pdev->bus->self; + } + + return NULL; +} +EXPORT_SYMBOL(pci_find_common_upstream_dev); diff --git a/include/linux/pci.h b/include/linux/pci.h index d58063e..8262b9e 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -860,6 +860,8 @@ static inline struct pci_dev *pci_get_bus_and_slot(unsigned int bus, } struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from); int pci_dev_present(const struct pci_device_id *ids); +struct pci_dev *pci_find_common_upstream_dev(struct pci_dev *from, + struct pci_dev *to); int pci_bus_read_config_byte(struct pci_bus *bus, unsigned int devfn, int where, u8 *val);
Adds an interface to find the first device which is upstream of both devices. Signed-off-by: Will Davis <wdavis@nvidia.com> --- drivers/pci/search.c | 25 +++++++++++++++++++++++++ include/linux/pci.h | 2 ++ 2 files changed, 27 insertions(+)