From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f179.google.com ([209.85.192.179]:50223 "EHLO mail-pd0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758733AbaDXRdx (ORCPT ); Thu, 24 Apr 2014 13:33:53 -0400 Received: by mail-pd0-f179.google.com with SMTP id g10so2158945pdj.38 for ; Thu, 24 Apr 2014 10:33:52 -0700 (PDT) Date: Thu, 24 Apr 2014 11:33:48 -0600 From: Bjorn Helgaas To: Jiang Liu Cc: Joerg Roedel , David Woodhouse , Yinghai Lu , Dan Williams , Vinod Koul , "Rafael J . Wysocki" , "Rafael J. Wysocki" , Len Brown , Ashok Raj , Yijing Wang , Tony Luck , iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug Message-ID: <20140424173348.GC29593@google.com> References: <1398150453-28141-1-git-send-email-jiang.liu@linux.intel.com> <1398150453-28141-18-git-send-email-jiang.liu@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1398150453-28141-18-git-send-email-jiang.liu@linux.intel.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Tue, Apr 22, 2014 at 03:07:28PM +0800, Jiang Liu wrote: > Finally enhance pci_root driver to support DMAR device hotplug when > hot-plugging PCI host bridges. > > Signed-off-by: Jiang Liu > --- > drivers/acpi/pci_root.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > index d388f13d48b4..aa8f549869f3 100644 > --- a/drivers/acpi/pci_root.c > +++ b/drivers/acpi/pci_root.c > @@ -33,6 +33,7 @@ > #include > #include > #include > +#include > #include > #include > #include /* for acpi_hest_init() */ > @@ -511,6 +512,7 @@ static int acpi_pci_root_add(struct acpi_device *device, > struct acpi_pci_root *root; > acpi_handle handle = device->handle; > int no_aspm = 0, clear_aspm = 0; > + bool hotadd = (system_state != SYSTEM_BOOTING); > > root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL); > if (!root) > @@ -557,6 +559,11 @@ static int acpi_pci_root_add(struct acpi_device *device, > strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS); > device->driver_data = root; > > + if (hotadd && dmar_device_hotplug(handle, true)) { Apparently "dmar_device_hotplug(handle, true)" means "add a DMAR device," and "dmar_device_hotplug(device->handle, false)" means "remove a DMAR device." I'm not really a fan of interfaces where one of the arguments selects between two completely different actions, because it's harder for a casual reader to see what's going on. I see how it simplifies your implementation a little bit, but I think it's more important to simplify for the reader. Bjorn