From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752654Ab3ATXyz (ORCPT ); Sun, 20 Jan 2013 18:54:55 -0500 Received: from hydra.sisk.pl ([212.160.235.94]:47864 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752206Ab3ATXyx (ORCPT ); Sun, 20 Jan 2013 18:54:53 -0500 From: "Rafael J. Wysocki" To: Jiang Liu Cc: Bjorn Helgaas , Jiang Liu , Yinghai Lu , Kenji Kaneshige , Yijing Wang , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Greg Kroah-Hartman , ACPI Devel Maling List , Toshi Kani , Myron Stowe Subject: Re: [RFC PATCH v5 3/8] PCI: add a blocking notifier chain for PCI bus addition/removal Date: Mon, 21 Jan 2013 00:54:54 +0100 Message-ID: <3583141.yG8QGivRYt@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.8.0-rc4; KDE/4.9.5; x86_64; ; ) In-Reply-To: <1358525267-14268-4-git-send-email-jiang.liu@huawei.com> References: <1358525267-14268-1-git-send-email-jiang.liu@huawei.com> <1358525267-14268-4-git-send-email-jiang.liu@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday, January 19, 2013 12:07:41 AM Jiang Liu wrote: > When adding/removing a PCI bus, some other components want to be > notified so they could update their states. For example, the pci_slot > driver needs to create/destroy PCI slots attaching to the PCI bus. > So introduce a dedicate blocking notifier chain for PCI bus > addition/removal events. It could be extended to support PCI device > addition/removal events in the future when needed. > > Signed-off-by: Jiang Liu > --- > drivers/pci/bus.c | 24 ++++++++++++++++++++++++ > drivers/pci/pci.h | 1 + > drivers/pci/probe.c | 2 ++ > drivers/pci/remove.c | 1 + > include/linux/pci.h | 12 ++++++++++++ > 5 files changed, 40 insertions(+) > > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c > index 4c843cd..8bbd3f2 100644 > --- a/drivers/pci/bus.c > +++ b/drivers/pci/bus.c > @@ -13,11 +13,33 @@ > #include > #include > #include > +#include > #include > #include > > #include "pci.h" > > +static BLOCKING_NOTIFIER_HEAD(pci_bus_notifier_chain); > + > +int pci_bus_register_notifier(struct notifier_block *nb) > +{ > + return blocking_notifier_chain_register(&pci_bus_notifier_chain, nb); > +} > + > +int pci_bus_unregister_notifier(struct notifier_block *nb) > +{ > + return blocking_notifier_chain_unregister(&pci_bus_notifier_chain, nb); > +} > + > +void pci_bus_call_notifier(struct pci_bus *bus, unsigned long code) > +{ > + int ret; > + > + ret = blocking_notifier_call_chain(&pci_bus_notifier_chain, > + code, bus); > + WARN_ON(ret != NOTIFY_DONE && ret != NOTIFY_OK); I'm not sure if this is a good idea. WARN_ON() is quite a heavy tool. > +} > + > void pci_add_resource_offset(struct list_head *resources, struct resource *res, > resource_size_t offset) > { > @@ -197,6 +219,8 @@ int pci_bus_add_child(struct pci_bus *bus) > if (retval) > return retval; > > + pci_bus_call_notifier(bus, PCI_NOTIFY_POST_BUS_ADD); > + > bus->is_added = 1; > > /* Create legacy_io and legacy_mem files for this bus */ > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index 7414094..988e4b4 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -208,6 +208,7 @@ extern int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, > extern int pci_resource_bar(struct pci_dev *dev, int resno, > enum pci_bar_type *type); > extern int pci_bus_add_child(struct pci_bus *bus); > +extern void pci_bus_call_notifier(struct pci_bus *bus, unsigned long code); > extern void pci_enable_ari(struct pci_dev *dev); > /** > * pci_ari_enabled - query ARI forwarding status > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index adb77c6..7db6528 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1679,6 +1679,8 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, > if (error) > goto class_dev_reg_err; > > + pci_bus_call_notifier(b, PCI_NOTIFY_POST_BUS_ADD); > + > /* Create legacy_io and legacy_mem files for this bus */ > pci_create_legacy_files(b); > > diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c > index 0d03026..2d8fbc8 100644 > --- a/drivers/pci/remove.c > +++ b/drivers/pci/remove.c > @@ -50,6 +50,7 @@ void pci_remove_bus(struct pci_bus *bus) > up_write(&pci_bus_sem); > if (bus->is_added) { > pci_remove_legacy_files(bus); > + pci_bus_call_notifier(bus, PCI_NOTIFY_PRE_BUS_DEL); > device_del(&bus->dev); > } > put_device(&bus->dev); > diff --git a/include/linux/pci.h b/include/linux/pci.h > index ee21795..12e5447 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1033,6 +1033,18 @@ const struct pci_device_id *pci_match_id(const struct pci_device_id *ids, > int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, > int pass); > > +/* > + * All notifiers below get called with the target struct pci_bus *bus as > + * an argument. > + * Note: all PCI bus notifier must return success. Currently there's no > + * error handling if any notifier returns error code. > + */ > +#define PCI_NOTIFY_POST_BUS_ADD 0x00000001 /* PCI bus has been added */ > +#define PCI_NOTIFY_PRE_BUS_DEL 0x00000002 /* PCI bus will be deleted */ I would call them PCI_EVENT_BUS_ADDED and PCI_EVENT_BUS_REMOVE, respectively. > + > +int pci_bus_register_notifier(struct notifier_block *nb); > +int pci_bus_unregister_notifier(struct notifier_block *nb); > + > void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *), > void *userdata); > int pci_cfg_space_size_ext(struct pci_dev *dev); Apart from the nitpicks above, looks good. Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.