From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933167AbaBAOYI (ORCPT ); Sat, 1 Feb 2014 09:24:08 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:61188 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932893AbaBAOYG (ORCPT ); Sat, 1 Feb 2014 09:24:06 -0500 From: "Rafael J. Wysocki" To: Yinghai Lu , Bjorn Helgaas Cc: Mika Westerberg , "linux-pci@vger.kernel.org" , "Rafael J. Wysocki" , Linus Torvalds , Linux Kernel Mailing List Subject: Re: [PATCH] Revert "PCI: Remove from bus_list and release resources in pci_release_dev()" Date: Sat, 01 Feb 2014 15:38:29 +0100 Message-ID: <14676899.LOmsodapl3@vostro.rjw.lan> User-Agent: KMail/4.11.4 (Linux/3.13.0+; KDE/4.11.4; x86_64; ; ) In-Reply-To: References: <20140130131236.GW18029@intel.com> <1676758.QjUXk2223P@vostro.rjw.lan> 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 Friday, January 31, 2014 05:56:30 PM Yinghai Lu wrote: > On Fri, Jan 31, 2014 at 3:34 PM, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki [...] > > diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c > > index 4ff36bfa785e..b8c93c90daf5 100644 > > --- a/drivers/pci/remove.c > > +++ b/drivers/pci/remove.c > > @@ -3,6 +3,20 @@ > > #include > > #include "pci.h" > > > > +static void pci_free_resources(struct pci_dev *dev) > > +{ > > + int i; > > + > > + msi_remove_pci_irq_vectors(dev); > > looks like you are in a rush. Why do you put back msi_remove_pci_irq_vectors? I simply did "git revert" and that's the result. Sorry about overlooking that, but your commit's changelog didn't mention removing it either. Updated revert follows. Thanks, Rafael --- From: Rafael J. Wysocki Subject: Revert "PCI: Remove from bus_list and release resources in pci_release_dev()" Revert commit ef83b0781a73 "PCI: Remove from bus_list and release resources in pci_release_dev()" that made some nasty race conditions become possible. For example, if a Thunderbolt link is unplugged and then replugged immediately, the pci_release_dev() resulting from the hot-remove code path may be racing with the hot-add code path which after that commit causes various kinds of breakage to happen (up to and including a hard crash of the whole system). Moreover, the problem that commit ef83b0781a73 attempted to address cannot happen any more after commit 8a4c5c329de7 "PCI: Check parent kobject in pci_destroy_dev()", because pci_destroy_dev() will now return immediately if it has already been executed for the given device. Note, however, that the invocation of msi_remove_pci_irq_vectors() removed by commit ef83b0781a73 from pci_free_resources() along with the other changes made by it is not added back because of subsequent code changes depending on that modification. Fixes: ef83b0781a73 (PCI: Remove from bus_list and release resources in pci_release_dev()) Reported-by: Mika Westerberg Signed-off-by: Rafael J. Wysocki --- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- drivers/pci/probe.c | 21 ++------------------- drivers/pci/remove.c | 17 +++++++++++++++++ 2 files changed, 19 insertions(+), 19 deletions(-) Index: linux-pm/drivers/pci/probe.c =================================================================== --- linux-pm.orig/drivers/pci/probe.c +++ linux-pm/drivers/pci/probe.c @@ -1208,18 +1208,6 @@ static void pci_release_capabilities(str pci_free_cap_save_buffers(dev); } -static void pci_free_resources(struct pci_dev *dev) -{ - int i; - - pci_cleanup_rom(dev); - for (i = 0; i < PCI_NUM_RESOURCES; i++) { - struct resource *res = dev->resource + i; - if (res->parent) - release_resource(res); - } -} - /** * pci_release_dev - free a pci device structure when all users of it are finished. * @dev: device that's been disconnected @@ -1229,14 +1217,9 @@ static void pci_free_resources(struct pc */ static void pci_release_dev(struct device *dev) { - struct pci_dev *pci_dev = to_pci_dev(dev); - - down_write(&pci_bus_sem); - list_del(&pci_dev->bus_list); - up_write(&pci_bus_sem); - - pci_free_resources(pci_dev); + struct pci_dev *pci_dev; + pci_dev = to_pci_dev(dev); pci_release_capabilities(pci_dev); pci_release_of_node(pci_dev); pcibios_release_device(pci_dev); Index: linux-pm/drivers/pci/remove.c =================================================================== --- linux-pm.orig/drivers/pci/remove.c +++ linux-pm/drivers/pci/remove.c @@ -3,6 +3,18 @@ #include #include "pci.h" +static void pci_free_resources(struct pci_dev *dev) +{ + int i; + + pci_cleanup_rom(dev); + for (i = 0; i < PCI_NUM_RESOURCES; i++) { + struct resource *res = dev->resource + i; + if (res->parent) + release_resource(res); + } +} + static void pci_stop_dev(struct pci_dev *dev) { pci_pme_active(dev, false); @@ -25,6 +37,11 @@ static void pci_destroy_dev(struct pci_d device_del(&dev->dev); + down_write(&pci_bus_sem); + list_del(&dev->bus_list); + up_write(&pci_bus_sem); + + pci_free_resources(dev); put_device(&dev->dev); }