From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 14FED1A054E for ; Wed, 11 Jun 2014 17:30:02 +1000 (EST) Message-ID: <1402471784.14780.45.camel@pasglop> Subject: Re: [PATCH] powerpc: reduce multi-hit of pcibios_setup_device() in hotplug From: Benjamin Herrenschmidt To: Wei Yang Date: Wed, 11 Jun 2014 17:29:44 +1000 In-Reply-To: <20140611071241.GA10729@richard> References: <1399530602-4231-1-git-send-email-weiyang@linux.vnet.ibm.com> <1399863559.17624.66.camel@pasglop> <20140611071241.GA10729@richard> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: Bjorn Helgaas , aik@au1.ibm.com, linuxppc-dev@lists.ozlabs.org, gwshan@linux.vnet.ibm.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2014-06-11 at 15:12 +0800, Wei Yang wrote: > Sorry for the long delay. It took me some time to investigate and test the code. > Currently, the hotplug by qemu monitor command line has been verified. Two pci > device on the same bus have been hotpluged one by one successfully. > > Another case in my mind is the EEH hotplug, which requires code in > Qemu/Sapphire/Kernel. I will did further test later. > > Below is the patch which is verified in guest with monitor command line. If my > understanding is not correct, please let me know :-) Please verify under pHyp, the code path are a bit different. Cheers, Ben. > >From 69c5f014836b24897356731c39cbaf18f4563573 Mon Sep 17 00:00:00 2001 > From: Wei Yang > Date: Tue, 10 Jun 2014 15:28:53 +0800 > Subject: [PATCH] powerpc/pci: Use bus->is_added in of_scan_bus() as in > general platform > > When scan the pci bus on general platform, it use bus->is_added to mark the > bus has been added successfully. While this flag is not used when the bus scan > relies on device node. Instead, it uses a particular parameter > "rescan_existing" to play the same role. > > This patch enables the bus->is_added when device node is used, drops the > "rescan_existing" parameter. Also it skip the pcibios_setup_bus_devices() > procedure when bus has already been added, since the pcibios_setup_device() > step is done in pci_device_add() when the bus is already added. > > Signed-off-by: Wei Yang > --- > arch/powerpc/kernel/pci_of_scan.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/arch/powerpc/kernel/pci_of_scan.c b/arch/powerpc/kernel/pci_of_scan.c > index 83c26d8..3e943ab 100644 > --- a/arch/powerpc/kernel/pci_of_scan.c > +++ b/arch/powerpc/kernel/pci_of_scan.c > @@ -334,10 +334,8 @@ static struct pci_dev *of_scan_pci_dev(struct pci_bus *bus, > * __of_scan_bus - given a PCI bus node, setup bus and scan for child devices > * @node: device tree node for the PCI bus > * @bus: pci_bus structure for the PCI bus > - * @rescan_existing: Flag indicating bus has already been set up > */ > -static void __of_scan_bus(struct device_node *node, struct pci_bus *bus, > - int rescan_existing) > +static void __of_scan_bus(struct device_node *node, struct pci_bus *bus) > { > struct device_node *child; > struct pci_dev *dev; > @@ -356,9 +354,11 @@ static void __of_scan_bus(struct device_node *node, struct pci_bus *bus, > /* Apply all fixups necessary. We don't fixup the bus "self" > * for an existing bridge that is being rescanned > */ > - if (!rescan_existing) > + if (!bus->is_added) { > pcibios_setup_bus_self(bus); > - pcibios_setup_bus_devices(bus); > + pcibios_setup_bus_devices(bus); > + bus->is_added = 1; > + } > > /* Now scan child busses */ > list_for_each_entry(dev, &bus->devices, bus_list) { > @@ -376,7 +376,7 @@ static void __of_scan_bus(struct device_node *node, struct pci_bus *bus, > */ > void of_scan_bus(struct device_node *node, struct pci_bus *bus) > { > - __of_scan_bus(node, bus, 0); > + __of_scan_bus(node, bus); > } > EXPORT_SYMBOL_GPL(of_scan_bus); > > @@ -390,7 +390,7 @@ EXPORT_SYMBOL_GPL(of_scan_bus); > */ > void of_rescan_bus(struct device_node *node, struct pci_bus *bus) > { > - __of_scan_bus(node, bus, 1); > + __of_scan_bus(node, bus); > } > EXPORT_SYMBOL_GPL(of_rescan_bus); > > -- > 1.7.9.5 > > > > > > >_______________________________________________ > >Linuxppc-dev mailing list > >Linuxppc-dev@lists.ozlabs.org > >https://lists.ozlabs.org/listinfo/linuxppc-dev >