From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: "Mickaël Salaün" <mic@digikod.net>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Mika Westerberg" <mika.westerberg@linux.intel.com>,
"Michael Ellerman" <mpe@ellerman.id.au>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"Philippe Mathieu-Daudé" <philmd@linaro.org>,
"Niklas Schnelle" <schnelle@linux.ibm.com>,
"Bjorn Helgaas" <helgaas@kernel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
"Pali Rohár" <pali@kernel.org>,
"Maciej W. Rozycki" <macro@orcam.me.uk>,
"Juergen Gross" <jgross@suse.com>,
"Dominik Brodowski" <linux@dominikbrodowski.net>,
linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org,
linux-arm-kernel@list
Cc: Miguel Ojeda <ojeda@kernel.org>,
Richard Henderson <richard.henderson@linaro.org>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
Russell King <linux@armlinux.org.uk>,
Andrew Lunn <andrew@lunn.ch>,
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
Gregory Clement <gregory.clement@bootlin.com>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Anatolij Gustschin <agust@denx.de>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
"David S. Miller" <davem@davemloft.net>,
Bjorn Helgaas <bhelgaas@google.com>,
Stefano Stabellini <sstabellini@kernel.org>
Subject: [PATCH v8 4/7] PCI: Document pci_bus_for_each_resource() to avoid confusion
Date: Thu, 30 Mar 2023 19:24:31 +0300 [thread overview]
Message-ID: <20230330162434.35055-5-andriy.shevchenko@linux.intel.com> (raw)
In-Reply-To: <20230330162434.35055-1-andriy.shevchenko@linux.intel.com>
There might be a confusion with the implementation of the
pci_bus_for_each_resources() due to side effect of Logical
OR. Document entire macro and explain how it works and why
the conditional needs to be like that.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
include/linux/pci.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 5cacd9e4c8cd..e3b3af606280 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1446,6 +1446,26 @@ 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: a varible to keep a pointer to the current resource
+ * @i: a variable to keep the 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; \
--
2.40.0.1.gaa8946217a0b
next prev parent reply other threads:[~2023-03-30 16:24 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-30 16:24 [PATCH v8 0/7] Add pci_dev_for_each_resource() helper and update users Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 1/7] kernel.h: Split out COUNT_ARGS() and CONCATENATE() Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 2/7] PCI: Introduce pci_resource_n() Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 3/7] PCI: Introduce pci_dev_for_each_resource() Andy Shevchenko
2023-03-30 16:24 ` Andy Shevchenko [this message]
2023-03-30 16:24 ` [PATCH v8 5/7] PCI: Allow pci_bus_for_each_resource() to take less arguments Andy Shevchenko
2023-04-05 11:50 ` Andy Shevchenko
2023-04-05 20:11 ` Bjorn Helgaas
2023-03-30 16:24 ` [PATCH v8 6/7] EISA: Convert to use less arguments in pci_bus_for_each_resource() Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 7/7] pcmcia: " Andy Shevchenko
2023-04-05 8:30 ` Andy Shevchenko
2023-04-04 16:11 ` [PATCH v8 0/7] Add pci_dev_for_each_resource() helper and update users Bjorn Helgaas
2023-04-05 8:28 ` Andy Shevchenko
2023-04-05 20:18 ` Bjorn Helgaas
2023-04-06 10:31 ` Andy Shevchenko
2023-05-09 18:21 ` Bjorn Helgaas
2023-05-12 10:56 ` Andy Shevchenko
2023-05-12 19:48 ` Bjorn Helgaas
2023-05-30 21:24 ` Bjorn Helgaas
2023-05-31 18:48 ` Jonas Gorski
2023-05-31 21:30 ` Bjorn Helgaas
2023-06-01 11:17 ` Jonas Gorski
2023-06-05 14:04 ` Andy Shevchenko
2023-06-01 16:25 ` Andy Shevchenko
2023-06-01 16:27 ` Andy Shevchenko
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