Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755761Ab3ENQwR (ORCPT ); Tue, 14 May 2013 12:52:17 -0400 Received: from mail-pa0-f49.google.com ([209.85.220.49]:46077 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751797Ab3ENQwP (ORCPT ); Tue, 14 May 2013 12:52:15 -0400 From: Jiang Liu To: Bjorn Helgaas , Yinghai Lu Cc: Jiang Liu , "Rafael J . Wysocki" , Greg Kroah-Hartman , Gu Zheng , Toshi Kani , Myron Stowe , Yijing Wang , Jiang Liu , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH v2, part 2 01/18] PCI: introduce hotplug-safe PCI bus iterators Date: Wed, 15 May 2013 00:51:45 +0800 Message-Id: <1368550322-1045-1-git-send-email-jiang.liu@huawei.com> X-Mailer: git-send-email 1.8.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10536 Lines: 313 Introduce hotplug-safe PCI bus iterators as below, which hold a reference on the returned PCI bus object. bool pci_bus_exists(int domain, int busnr); struct pci_bus *pci_get_bus(int domain, int busnr); struct pci_bus *pci_get_next_bus(struct pci_bus *from); struct pci_bus *pci_get_next_root_bus(struct pci_bus *from); #define for_each_pci_bus(b) for (b = NULL; (b = pci_get_next_bus(b)); ) #define for_each_pci_root_bus(b) \ for (b = NULL; (b = pci_get_next_root_bus(b)); ) The long-term goal is to remove hotplug-unsafe pci_find_bus(), pci_find_next_bus() and the global pci_root_buses list. These new interfaces may be a littler slower than existing interfaces, but it should be acceptable because they are not used on hot paths. Signed-off-by: Jiang Liu Cc: linux-pci@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- drivers/pci/pci.h | 1 + drivers/pci/probe.c | 2 +- drivers/pci/search.c | 159 +++++++++++++++++++++++++++++++++++++++++---------- include/linux/pci.h | 23 +++++++- 4 files changed, 153 insertions(+), 32 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 68678ed..8fe15f6 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -126,6 +126,7 @@ static inline void pci_remove_legacy_files(struct pci_bus *bus) { return; } /* Lock for read/write access to pci device and bus lists */ extern struct rw_semaphore pci_bus_sem; +extern struct class pcibus_class; extern raw_spinlock_t pci_lock; diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index e59433a..6b77333 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -93,7 +93,7 @@ static void release_pcibus_dev(struct device *dev) kfree(pci_bus); } -static struct class pcibus_class = { +struct class pcibus_class = { .name = "pci_bus", .dev_release = &release_pcibus_dev, .dev_attrs = pcibus_dev_attrs, diff --git a/drivers/pci/search.c b/drivers/pci/search.c index d0627fa..16ccaf8 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -52,20 +52,27 @@ pci_find_upstream_pcie_bridge(struct pci_dev *pdev) return tmp; } -static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr) +struct pci_bus_match_arg { + int domain; + int bus; +}; + +static int pci_match_bus(struct device *dev, const void *data) { - struct pci_bus* child; - struct list_head *tmp; + struct pci_bus *bus = to_pci_bus(dev); + const struct pci_bus_match_arg *arg = data; - if(bus->number == busnr) - return bus; + return (pci_domain_nr(bus) == arg->domain && bus->number == arg->bus); +} - list_for_each(tmp, &bus->children) { - child = pci_do_find_bus(pci_bus_b(tmp), busnr); - if(child) - return child; - } - return NULL; +static int pci_match_next_bus(struct device *dev, const void *data) +{ + return 1; +} + +static int pci_match_next_root_bus(struct device *dev, const void *data) +{ + return pci_is_root_bus(to_pci_bus(dev)); } /** @@ -76,20 +83,19 @@ static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr) * Given a PCI bus number and domain number, the desired PCI bus is located * in the global list of PCI buses. If the bus is found, a pointer to its * data structure is returned. If no bus is found, %NULL is returned. + * + * Note: it's not hotplug safe, the returned bus may be destroyed at any time. + * Please use pci_get_bus() instead which holds a reference on the returned + * PCI bus. */ -struct pci_bus * pci_find_bus(int domain, int busnr) +struct pci_bus *pci_find_bus(int domain, int busnr) { - struct pci_bus *bus = NULL; - struct pci_bus *tmp_bus; + struct pci_bus *bus; - while ((bus = pci_find_next_bus(bus)) != NULL) { - if (pci_domain_nr(bus) != domain) - continue; - tmp_bus = pci_do_find_bus(bus, busnr); - if (tmp_bus) - return tmp_bus; - } - return NULL; + bus = pci_get_bus(domain, busnr); + pci_bus_put(bus); + + return bus; } /** @@ -100,21 +106,114 @@ struct pci_bus * pci_find_bus(int domain, int busnr) * initiated by passing %NULL as the @from argument. Otherwise if * @from is not %NULL, searches continue from next device on the * global list. + * + * Note: it's not hotplug safe, the returned bus may be destroyed at any time. + * Please use pci_get_next_root_bus() instead which holds a reference + * on the returned PCI root bus. */ struct pci_bus * pci_find_next_bus(const struct pci_bus *from) { - struct list_head *n; - struct pci_bus *b = NULL; + struct device *dev = from ? (struct device *)&from->dev : NULL; + + dev = class_find_device(&pcibus_class, dev, NULL, + &pci_match_next_root_bus); + if (dev) { + put_device(dev); + return to_pci_bus(dev); + } + + return NULL; +} + +bool pci_bus_exists(int domain, int busnr) +{ + struct device *dev; + struct pci_bus_match_arg arg = { domain, busnr }; WARN_ON(in_interrupt()); - down_read(&pci_bus_sem); - n = from ? from->node.next : pci_root_buses.next; - if (n != &pci_root_buses) - b = pci_bus_b(n); - up_read(&pci_bus_sem); - return b; + dev = class_find_device(&pcibus_class, NULL, &arg, &pci_match_bus); + if (dev) + put_device(dev); + + return dev != NULL; +} +EXPORT_SYMBOL(pci_bus_exists); + +/** + * pci_get_bus - locate PCI bus from a given domain and bus number + * @domain: number of PCI domain to search + * @busnr: number of desired PCI bus + * + * Given a PCI bus number and domain number, the desired PCI bus is located. + * If the bus is found, a pointer to its data structure is returned. + * If no bus is found, %NULL is returned. + * Caller needs to release the returned bus by calling pci_bus_put(). + */ +struct pci_bus *pci_get_bus(int domain, int busnr) +{ + struct device *dev; + struct pci_bus_match_arg arg = { domain, busnr }; + + WARN_ON(in_interrupt()); + dev = class_find_device(&pcibus_class, NULL, &arg, &pci_match_bus); + if (dev) + return to_pci_bus(dev); + + return NULL; +} +EXPORT_SYMBOL(pci_get_bus); + +/** + * pci_get_next_bus - begin or continue searching for a PCI bus + * @from: Previous PCI bus found, or %NULL for new search. + * + * Iterates through the list of known PCI busses. If a PCI bus is found, + * the reference count to the bus is incremented and a pointer to it is + * returned. Otherwise, %NULL is returned. A new search is initiated by + * passing %NULL as the @from argument. Otherwise if @from is not %NULL, + * searches continue from next bus on the global list. The reference count + * for @from is always decremented if it is not %NULL. + */ +struct pci_bus *pci_get_next_bus(struct pci_bus *from) +{ + struct device *dev = from ? &from->dev : NULL; + + WARN_ON(in_interrupt()); + dev = class_find_device(&pcibus_class, dev, NULL, &pci_match_next_bus); + pci_bus_put(from); + if (dev) + return to_pci_bus(dev); + + return NULL; +} +EXPORT_SYMBOL(pci_get_next_bus); + +/** + * pci_find_next_root_bus - begin or continue searching for a PCI root bus + * @from: Previous PCI bus found, or %NULL for new search. + * + * Iterates through the list of known PCI root busses. If a PCI bus is found, + * the reference count to the root bus is incremented and a pointer to it is + * returned. Otherwise, %NULL is returned. A new search is initiated by + * passing %NULL as the @from argument. Otherwise if @from is not %NULL, + * searches continue from next root bus on the global list. The reference + * count for @from is always decremented if it is not %NULL. + */ +struct pci_bus *pci_get_next_root_bus(struct pci_bus *from) +{ + struct device *dev = from ? &from->dev : NULL; + + WARN_ON(in_interrupt()); + dev = class_find_device(&pcibus_class, dev, NULL, + &pci_match_next_root_bus); + pci_bus_put(from); + if (dev) + return to_pci_bus(dev); + + return NULL; } +EXPORT_SYMBOL(pci_get_next_root_bus); /** * pci_get_slot - locate PCI device for a given PCI slot diff --git a/include/linux/pci.h b/include/linux/pci.h index cc4ce27..c88d4e6 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -454,6 +454,9 @@ struct pci_bus { #define pci_bus_b(n) list_entry(n, struct pci_bus, node) #define to_pci_bus(n) container_of(n, struct pci_bus, dev) +#define for_each_pci_bus(b) for (b = NULL; (b = pci_get_next_bus(b)); ) +#define for_each_pci_root_bus(b) \ + for (b = NULL; (b = pci_get_next_root_bus(b)); ) /* * Returns true if the pci bus is root (behind host-pci bridge), @@ -718,7 +721,6 @@ void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region, void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res, struct pci_bus_region *region); void pcibios_scan_specific_bus(int busn); -struct pci_bus *pci_find_bus(int domain, int busnr); void pci_bus_add_devices(const struct pci_bus *bus); struct pci_bus * __deprecated pci_scan_bus_parented(struct device *parent, int bus, struct pci_ops *ops, void *sysdata); @@ -778,8 +780,15 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap); int pci_find_next_ext_capability(struct pci_dev *dev, int pos, int cap); int pci_find_ht_capability(struct pci_dev *dev, int ht_cap); int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap); + +struct pci_bus *pci_find_bus(int domain, int busnr); struct pci_bus *pci_find_next_bus(const struct pci_bus *from); +bool pci_bus_exists(int domain, int busnr); +struct pci_bus *pci_get_bus(int domain, int busnr); +struct pci_bus *pci_get_next_bus(struct pci_bus *from); +struct pci_bus *pci_get_next_root_bus(struct pci_bus *from); + struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from); struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, @@ -1429,6 +1438,18 @@ static inline void pci_unblock_cfg_access(struct pci_dev *dev) static inline struct pci_bus *pci_find_next_bus(const struct pci_bus *from) { return NULL; } +static inline bool pci_bus_exists(int domain, int busnr) +{ return false; } + +static inline struct pci_bus *pci_get_bus(int domain, int busnr) +{ return NULL; } + +static inline struct pci_bus *pci_get_next_bus(struct pci_bus *from) +{ return NULL; } + +static inline struct pci_bus *pci_get_next_root_bus(struct pci_bus *from) +{ return NULL; } + static inline struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn) { return NULL; } -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/