From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Helgaas Subject: Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug Date: Thu, 24 Apr 2014 11:33:48 -0600 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" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1398150453-28141-18-git-send-email-jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Jiang Liu Cc: Tony Luck , linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Vinod Koul , David Woodhouse , "Rafael J . Wysocki" , "Rafael J. Wysocki" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Dan Williams , Yinghai Lu , Len Brown List-Id: iommu@lists.linux-foundation.org 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