Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751506Ab2HaFnA (ORCPT ); Fri, 31 Aug 2012 01:43:00 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:36026 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751229Ab2HaFm6 (ORCPT ); Fri, 31 Aug 2012 01:42:58 -0400 MIME-Version: 1.0 In-Reply-To: <1346357766-14030-2-git-send-email-toshi.kani@hp.com> References: <1346357766-14030-1-git-send-email-toshi.kani@hp.com> <1346357766-14030-2-git-send-email-toshi.kani@hp.com> From: Bjorn Helgaas Date: Thu, 30 Aug 2012 22:42:37 -0700 Message-ID: Subject: Re: [RFC PATCH 1/5] ACPI: Add acpi_lookup_driver() function To: Toshi Kani Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, lenb@kernel.org, liuj97@gmail.com, isimatu.yasuaki@jp.fujitsu.com Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4007 Lines: 115 On Thu, Aug 30, 2012 at 1:16 PM, Toshi Kani wrote: > Added acpi_lookup_driver(), which looks up an associated driver > for the notified ACPI device object by walking through the list > of ACPI drivers. > > Signed-off-by: Toshi Kani > --- > drivers/acpi/scan.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++ > include/acpi/acpi_bus.h | 2 + > 2 files changed, 67 insertions(+), 0 deletions(-) > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index d1ecca2..d0e0d18 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -1630,3 +1630,68 @@ int __init acpi_scan_init(void) > > return result; > } > + > +static int acpi_match_driver(struct device_driver *drv, void *data) > +{ > + struct acpi_driver *driver = to_acpi_driver(drv); > + struct acpi_device *device = (struct acpi_device *) data; > + int ret; > + > + ret = acpi_match_device_ids(device, driver->ids); > + if (!ret) > + device->driver = driver; > + > + return !ret; > +} > + > +/** > + * acpi_lookup_driver: Look up a driver for the notified ACPI device > + * @handle: ACPI handle of the notified device object > + * @event: Notify event > + * > + * Look up an associated driver for the notified ACPI device object > + * by walking through the list of ACPI drivers. > + */ > +struct acpi_driver *acpi_lookup_driver(acpi_handle handle, u32 event) > +{ > + struct acpi_device *device; > + struct acpi_driver *driver = NULL; > + unsigned long long sta; > + int type; > + int ret; > + > + /* allocate a temporary device object */ > + device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL); > + if (!device) { > + pr_err(PREFIX "No memory to allocate a tmp device\n"); > + return NULL; > + } > + > + ret = acpi_bus_type_and_status(handle, &type, &sta); > + if (ret) { > + pr_err(PREFIX "Failed to get type of device\n"); > + goto out; > + } > + > + /* setup this temporary device object */ > + INIT_LIST_HEAD(&device->pnp.ids); > + device->device_type = type; > + device->handle = handle; > + device->parent = acpi_bus_get_parent(handle); > + device->dev.bus = &acpi_bus_type; > + device->driver = NULL; > + STRUCT_TO_INT(device->status) = sta; > + device->status.present = 1; > + > + /* set HID to this device object */ > + acpi_device_set_id(device); > + > + /* lookup a matching driver */ > + (void) bus_for_each_drv(device->dev.bus, NULL, > + device, acpi_match_driver); > + driver = device->driver; This path is used when we receive a Notify to a device and a matching driver has been registered, but the driver is not bound to the device. For example, it may be a newly-added device where we haven't bound a driver to it yet. Is there anything that prevents us from unloading the driver between here (the point where we capture the "struct acpi_driver *") and the point where we call "driver->ops.sys_notify"? > + > +out: > + kfree(device); > + return driver; > +} > diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h > index bde976e..a773b46 100644 > --- a/include/acpi/acpi_bus.h > +++ b/include/acpi/acpi_bus.h > @@ -345,6 +345,8 @@ extern int unregister_acpi_notifier(struct notifier_block *); > > extern int register_acpi_bus_notifier(struct notifier_block *nb); > extern void unregister_acpi_bus_notifier(struct notifier_block *nb); > +extern struct acpi_driver *acpi_lookup_driver(acpi_handle handle, u32 event); > + > /* > * External Functions > */ > -- > 1.7.7.6 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/