From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753544Ab3LCMew (ORCPT ); Tue, 3 Dec 2013 07:34:52 -0500 Received: from mail-ee0-f54.google.com ([74.125.83.54]:58687 "EHLO mail-ee0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752881Ab3LCMet (ORCPT ); Tue, 3 Dec 2013 07:34:49 -0500 Date: Tue, 3 Dec 2013 12:34:46 +0000 From: Kim Phillips To: linux-kernel@vger.kernel.org, Greg Kroah-Hartman Cc: kvm@vger.kernel.org, scottwood@freescale.com, R65777@freescale.com, B07421@freescale.com, B08248@freescale.com, christoffer.dall@linaro.org, alex.williamson@redhat.com, a.motakis@virtualopensystems.com, agraf@suse.de, B16395@freescale.com Subject: [REPOST][PATCH 1/2] driver core: Add new device_driver flag to allow binding via sysfs only Message-Id: <20131203123446.42fbff34a8ebd7afd38159a5@linaro.org> X-Mailer: Sylpheed 3.4.0beta5 (GTK+ 2.24.20; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org VFIO supports pass-through of devices to user space - for sake of illustration, say a PCI e1000 device: - the e1000 is first unbound from the PCI e1000 driver via sysfs - the vfio-pci driver is told via new_id that it now handles e1000 devices - the e1000 is explicitly bound to vfio-pci through sysfs However, now we have two drivers in the system that both handle e1000 devices. A hotplug event could then occur and it is ambiguous as to which driver will claim the device. The desired semantics is that vfio-pci is only bound to devices by explicit request in sysfs. This patch makes this possible by introducing a sysfs_bind_only flag in struct device_driver. Signed-off-by: Stuart Yoder Signed-off-by: Kim Phillips --- rebased onto 3.13-rc2, and reposted from first submission which recieved no comments: https://lkml.org/lkml/2013/10/11/53 drivers/base/dd.c | 5 ++++- include/linux/device.h | 2 ++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 0605176..b83b16d 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -389,7 +389,7 @@ static int __device_attach(struct device_driver *drv, void *data) { struct device *dev = data; - if (!driver_match_device(drv, dev)) + if (drv->sysfs_bind_only || !driver_match_device(drv, dev)) return 0; return driver_probe_device(drv, dev); @@ -476,6 +476,9 @@ static int __driver_attach(struct device *dev, void *data) */ int driver_attach(struct device_driver *drv) { + if (drv->sysfs_bind_only) + return 0; + return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); } EXPORT_SYMBOL_GPL(driver_attach); diff --git a/include/linux/device.h b/include/linux/device.h index 952b010..ed441d1 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -200,6 +200,7 @@ extern struct klist *bus_get_device_klist(struct bus_type *bus); * @owner: The module owner. * @mod_name: Used for built-in modules. * @suppress_bind_attrs: Disables bind/unbind via sysfs. + * @sysfs_bind_only: Only allow bind/unbind via sysfs. * @of_match_table: The open firmware table. * @acpi_match_table: The ACPI match table. * @probe: Called to query the existence of a specific device, @@ -233,6 +234,7 @@ struct device_driver { const char *mod_name; /* used for built-in modules */ bool suppress_bind_attrs; /* disables bind/unbind via sysfs */ + bool sysfs_bind_only; /* only allow bind/unbind via sysfs */ const struct of_device_id *of_match_table; const struct acpi_device_id *acpi_match_table; -- 1.8.5