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| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2023-03-30 19:24:31 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2023-04-04 10:47:11 -0500 |
| commit | ceb928be5cab32043f230bcb1adeb0a9a9b8f0f2 (patch) | |
| tree | 1b9e8f0535db2694b894ff577cffca609839f43b /include/linux/pci.h | |
| parent | 09cc900632400079619e9154604fd299c2cc9a5a (diff) | |
| download | linux-ceb928be5cab32043f230bcb1adeb0a9a9b8f0f2.tar.gz linux-ceb928be5cab32043f230bcb1adeb0a9a9b8f0f2.tar.bz2 linux-ceb928be5cab32043f230bcb1adeb0a9a9b8f0f2.zip | |
PCI: Document pci_bus_for_each_resource()
There might be confusion about why pci_bus_for_each_resource() uses
Logical OR. Document the entire macro and explain how it works and why the
conditional needs to be like that.
Link: https://lore.kernel.org/r/20230330162434.35055-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'include/linux/pci.h')
| -rw-r--r-- | include/linux/pci.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/pci.h b/include/linux/pci.h index 2234ef961bfe..db3155562320 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1444,6 +1444,26 @@ int devm_request_pci_bus_resources(struct device *dev, /* Temporary until new and working PCI SBR API in place */ int pci_bridge_secondary_bus_reset(struct pci_dev *dev); +/** + * pci_bus_for_each_resource - iterate over PCI bus resources + * @bus: the PCI bus + * @res: pointer to the current resource + * @i: index of the current resource + * + * Iterate over PCI bus resources. The first part is to go over PCI bus + * resource array, which has at most the %PCI_BRIDGE_RESOURCE_NUM entries. + * After that continue with the separate list of the additional resources, + * if not empty. That's why the Logical OR is being used. + * + * Possible usage: + * + * struct pci_bus *bus = ...; + * struct resource *res; + * unsigned int i; + * + * pci_bus_for_each_resource(bus, res, i) + * pr_info("PCI bus resource[%u]: %pR\n", i, res); + */ #define pci_bus_for_each_resource(bus, res, i) \ for (i = 0; \ (res = pci_bus_resource_n(bus, i)) || i < PCI_BRIDGE_RESOURCE_NUM; \ |