From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f174.google.com ([209.85.217.174]:61644 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757022Ab2HTP2H (ORCPT ); Mon, 20 Aug 2012 11:28:07 -0400 Received: by lbbgj3 with SMTP id gj3so3362683lbb.19 for ; Mon, 20 Aug 2012 08:28:05 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20120817233100.10973.59521.stgit@bhelgaas.mtv.corp.google.com> <20120817233626.10973.57304.stgit@bhelgaas.mtv.corp.google.com> From: Bjorn Helgaas Date: Mon, 20 Aug 2012 09:27:44 -0600 Message-ID: Subject: Re: [PATCH v2 08/16] PCI: Stop and remove devices in one pass To: Yinghai Lu Cc: linux-pci@vger.kernel.org, linux-pcmcia@lists.infradead.org, Kenji Kaneshige Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-pci-owner@vger.kernel.org List-ID: On Fri, Aug 17, 2012 at 7:21 PM, Yinghai Lu wrote: > On Fri, Aug 17, 2012 at 4:36 PM, Bjorn Helgaas wrote: >> Previously, when we removed a PCI device, we made two passes over the >> hierarchy rooted at the device. In the first pass, we stopped all >> the devices, and in the second, we removed them. >> >> This patch combines the two passes into one so that we remove a device as >> soon as it and all its children have been stopped. >> >> Note that we previously stopped devices in reverse order and removed them >> in forward order. Now we stop and remove them in reverse order. >> >> Signed-off-by: Bjorn Helgaas >> --- >> drivers/pci/remove.c | 42 +++++++----------------------------------- >> 1 files changed, 7 insertions(+), 35 deletions(-) > > looks like your cleanup will have some conflict with my pci root bus > hot plug branch. Yes, indeed, they have serious conflicts. > http://git.kernel.org/?p=linux/kernel/git/yinghai/linux-yinghai.git;a=blob;f=drivers/pci/remove.c;h=f672731922f8db619fb36db05dbd9c27f3253c19;hb=refs/heads/for-pci-root-bus-hotplug > > it add pci_stop_and_remove_bus and it depends on some functions that > you kill in this patch set. Do you have any suggestions on how to proceed? In my opinion, remove.c is a bit of a rat's nest right now. It took me quite a long time to sort out what's going on, but when you finally get down to the bottom, it's actually very simple. So I'd really like to clean it up and expose that simple structure before we throw more stuff into it. After my cleanup, pci_stop_and_remove_bus_device() and pci_remove_bus() are the only exported interfaces left. How hard would it be to implement host bridge remove on top of that? I think it's OK (and even preferable) if the host bridge-related code can be segregated by itself rather than being sprinkled around through lots of PCI code. So maybe the pci_is_root_bus() and pci_stop_host_bridge() stuff below could be in some sort of host bridge interface that just calls the code in remove.c. > 180 void pci_stop_and_remove_bus(struct pci_bus *bus) > 181 { > 182 struct pci_host_bridge *host_bridge = NULL; > 183 struct pci_dev *pci_bridge = NULL; > 184 > 185 pci_stop_bus_devices(bus); > 186 > 187 if (pci_is_root_bus(bus)) { > 188 host_bridge = to_pci_host_bridge(bus->bridge); > 189 get_device(&host_bridge->dev); > 190 pci_stop_host_bridge(host_bridge); > 191 } else > 192 pci_bridge = bus->self; > 193 > 194 __pci_remove_bus_devices(bus); > 195 > 196 pci_remove_bus(bus); > 197 > 198 if (host_bridge) { > 199 host_bridge->bus = NULL; > 200 put_device(&host_bridge->dev); > 201 } > 202 > 203 if (pci_bridge) > 204 pci_bridge->subordinate = NULL; > 205 } > > Yinghai