From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: "Rafael J. Wysocki" To: ACPI Devel Maling List Cc: Bjorn Helgaas , Aaron Lu , Linux Kernel Mailing List , Linux PCI , Mika Westerberg Subject: [PATCH v2 3/13] ACPI / hotplug / PCI: Simplify disable_slot() Date: Sun, 02 Feb 2014 01:23:30 +0100 Message-ID: <1662988.VQzBl3dffR@vostro.rjw.lan> In-Reply-To: <1935791.liE9ZlzmO9@vostro.rjw.lan> References: <2217793.001RY6hKlo@vostro.rjw.lan> <1935791.liE9ZlzmO9@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: From: Rafael J. Wysocki After recent PCI core changes related to the rescan/remove locking, the ACPIPHP's disable_slot() function is only called under the general PCI rescan/remove lock, so it doesn't have to use dev_in_slot() any more to avoid race conditions. Make it simply walk the devices on the bus and drop the ones in the slot being disabled and drop dev_in_slot() which has no more users. Moreover, to avoid problems described in the changelog of commit 29ed1f29b68a (PCI: pciehp: Fix null pointer deref when hot-removing SR-IOV device), make disable_slot() carry out the list walk in reverse order. Signed-off-by: Rafael J. Wysocki --- drivers/pci/hotplug/acpiphp_glue.c | 28 +++++----------------------- 1 file changed, 5 insertions(+), 23 deletions(-) Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c =================================================================== --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c @@ -604,32 +604,15 @@ static void __ref enable_slot(struct acp } } -/* return first device in slot, acquiring a reference on it */ -static struct pci_dev *dev_in_slot(struct acpiphp_slot *slot) -{ - struct pci_bus *bus = slot->bus; - struct pci_dev *dev; - struct pci_dev *ret = NULL; - - down_read(&pci_bus_sem); - list_for_each_entry(dev, &bus->devices, bus_list) - if (PCI_SLOT(dev->devfn) == slot->device) { - ret = pci_dev_get(dev); - break; - } - up_read(&pci_bus_sem); - - return ret; -} - /** * disable_slot - disable a slot * @slot: ACPI PHP slot */ static void disable_slot(struct acpiphp_slot *slot) { + struct pci_bus *bus = slot->bus; + struct pci_dev *dev, *prev; struct acpiphp_func *func; - struct pci_dev *pdev; /* * enable_slot() enumerates all functions in this device via @@ -637,10 +620,9 @@ static void disable_slot(struct acpiphp_ * methods (_EJ0, etc.) or not. Therefore, we remove all functions * here. */ - while ((pdev = dev_in_slot(slot))) { - pci_stop_and_remove_bus_device(pdev); - pci_dev_put(pdev); - } + list_for_each_entry_safe_reverse(dev, prev, &bus->devices, bus_list) + if (PCI_SLOT(dev->devfn) == slot->device) + pci_stop_and_remove_bus_device(dev); list_for_each_entry(func, &slot->funcs, sibling) acpiphp_bus_trim(func_to_handle(func));