| Message ID | 1346357766-14030-2-git-send-email-toshi.kani@hp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Aug 30, 2012 at 1:16 PM, Toshi Kani <toshi.kani@hp.com> 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 <toshi.kani@hp.com> > --- > 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-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-08-30 at 22:42 -0700, Bjorn Helgaas wrote: > On Thu, Aug 30, 2012 at 1:16 PM, Toshi Kani <toshi.kani@hp.com> 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 <toshi.kani@hp.com> > > --- > > 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"? Hi Bjorn, That's a very good question. I will look into how we protect a driver from unloading when we try to attach & probe a driver in the acpi_add_single_object() path, and see if we can use a similar way to protect it here as well. Thanks, -Toshi > > + > > +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-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
(snip) : > > > + > > > + /* 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"? > > Hi Bjorn, > > That's a very good question. I will look into how we protect a driver > from unloading when we try to attach & probe a driver in the > acpi_add_single_object() path, and see if we can use a similar way to > protect it here as well. I have protected this path in version 2, which I just sent out. It calls .sys_notify() directly from bus_for_each_drv(), which protects the driver entry by increasing its reference count while the callback function is being called. Thanks, -Toshi -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; + +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 */
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 <toshi.kani@hp.com> --- drivers/acpi/scan.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++ include/acpi/acpi_bus.h | 2 + 2 files changed, 67 insertions(+), 0 deletions(-)