* [Patch 4/4] Driver core: Don't fail attaching the device if it cannot be bound.
@ 2006-10-17 11:06 Cornelia Huck
2006-10-17 16:04 ` Alan Stern
0 siblings, 1 reply; 4+ messages in thread
From: Cornelia Huck @ 2006-10-17 11:06 UTC (permalink / raw)
To: Greg K-H; +Cc: Alan Stern, Duncan Sands, linux-kernel
From: Cornelia Huck <cornelia.huck@de.ibm.com>
Don't fail bus_attach_device(), even if the device cannot be bound.
If dev->driver has been specified, reset it to NULL if device_bind_driver()
failed and add the device as an unbound device. As a result, bus_attach_device()
now cannot fail, and we can remove some checking from device_add().
Also remove an unneeded check in bus_rescan_devices_helper().
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
drivers/base/base.h | 2 +-
drivers/base/bus.c | 13 +++++--------
drivers/base/core.c | 5 +----
drivers/base/dd.c | 6 +++++-
4 files changed, 12 insertions(+), 14 deletions(-)
--- linux-2.6.orig/drivers/base/dd.c
+++ linux-2.6/drivers/base/dd.c
@@ -221,7 +221,7 @@ static int device_probe_drivers(void *da
*
* Returns 1 if the device was bound to a driver;
* 0 if no matching device was found or multithreaded probing is done;
- * error code otherwise.
+ * -ENODEV if the device is not registered.
*
* When called for a USB interface, @dev->parent->sem must be held.
*/
@@ -235,6 +235,10 @@ int device_attach(struct device * dev)
ret = device_bind_driver(dev);
if (ret == 0)
ret = 1;
+ else {
+ dev->driver = NULL;
+ ret = 0;
+ }
} else {
if (dev->bus->multithread_probe)
probe_task = kthread_run(device_probe_drivers, dev,
--- linux-2.6.orig/drivers/base/core.c
+++ linux-2.6/drivers/base/core.c
@@ -479,8 +479,7 @@ int device_add(struct device *dev)
if ((error = bus_add_device(dev)))
goto BusError;
kobject_uevent(&dev->kobj, KOBJ_ADD);
- if ((error = bus_attach_device(dev)))
- goto AttachError;
+ bus_attach_device(dev);
if (parent)
klist_add_tail(&dev->knode_parent, &parent->klist_children);
@@ -499,8 +498,6 @@ int device_add(struct device *dev)
kfree(class_name);
put_device(dev);
return error;
- AttachError:
- bus_remove_device(dev);
BusError:
device_pm_remove(dev);
PMError:
--- linux-2.6.orig/drivers/base/base.h
+++ linux-2.6/drivers/base/base.h
@@ -16,7 +16,7 @@ extern int cpu_dev_init(void);
extern int attribute_container_init(void);
extern int bus_add_device(struct device * dev);
-extern int bus_attach_device(struct device * dev);
+extern void bus_attach_device(struct device * dev);
extern void bus_remove_device(struct device * dev);
extern struct bus_type *get_bus(struct bus_type * bus);
extern void put_bus(struct bus_type * bus);
--- linux-2.6.orig/drivers/base/bus.c
+++ linux-2.6/drivers/base/bus.c
@@ -406,21 +406,20 @@ out_put:
* - Add device to bus's list of devices.
* - Try to attach to driver.
*/
-int bus_attach_device(struct device * dev)
+void bus_attach_device(struct device * dev)
{
struct bus_type *bus = dev->bus;
- int ret = 0;
+ int ret;
if (bus) {
dev->is_registered = 1;
ret = device_attach(dev);
- if (ret >= 0) {
+ BUG_ON(ret < 0);
+ if (ret >= 0)
klist_add_tail(&dev->knode_bus, &bus->klist_devices);
- ret = 0;
- } else
+ else
dev->is_registered = 0;
}
- return ret;
}
/**
@@ -593,8 +592,6 @@ static int __must_check bus_rescan_devic
ret = device_attach(dev);
if (dev->parent)
up(&dev->parent->sem);
- if (ret > 0)
- ret = 0;
}
return ret < 0 ? ret : 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Patch 4/4] Driver core: Don't fail attaching the device if it cannot be bound.
2006-10-17 11:06 [Patch 4/4] Driver core: Don't fail attaching the device if it cannot be bound Cornelia Huck
@ 2006-10-17 16:04 ` Alan Stern
2006-10-17 16:25 ` Cornelia Huck
0 siblings, 1 reply; 4+ messages in thread
From: Alan Stern @ 2006-10-17 16:04 UTC (permalink / raw)
To: Cornelia Huck; +Cc: Greg K-H, Duncan Sands, linux-kernel
On Tue, 17 Oct 2006, Cornelia Huck wrote:
> From: Cornelia Huck <cornelia.huck@de.ibm.com>
>
> Don't fail bus_attach_device(), even if the device cannot be bound.
>
> If dev->driver has been specified, reset it to NULL if device_bind_driver()
> failed and add the device as an unbound device. As a result, bus_attach_device()
> now cannot fail, and we can remove some checking from device_add().
>
> Also remove an unneeded check in bus_rescan_devices_helper().
The other patches look good, and so does this one except for one small
thing:
> -int bus_attach_device(struct device * dev)
> +void bus_attach_device(struct device * dev)
> {
> struct bus_type *bus = dev->bus;
> - int ret = 0;
> + int ret;
>
> if (bus) {
> dev->is_registered = 1;
> ret = device_attach(dev);
> - if (ret >= 0) {
> + BUG_ON(ret < 0);
> + if (ret >= 0)
> klist_add_tail(&dev->knode_bus, &bus->klist_devices);
> - ret = 0;
> - } else
> + else
> dev->is_registered = 0;
It looks odd to test the value of ret when you've just crashed the system
if ret < 0. You probably should change the BUG_ON to a WARN_ON or
something similar.
Alan Stern
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Patch 4/4] Driver core: Don't fail attaching the device if it cannot be bound.
2006-10-17 16:04 ` Alan Stern
@ 2006-10-17 16:25 ` Cornelia Huck
2006-10-17 19:43 ` Alan Stern
0 siblings, 1 reply; 4+ messages in thread
From: Cornelia Huck @ 2006-10-17 16:25 UTC (permalink / raw)
To: Alan Stern; +Cc: Greg K-H, Duncan Sands, linux-kernel
On Tue, 17 Oct 2006 12:04:28 -0400 (EDT),
Alan Stern <stern@rowland.harvard.edu> wrote:
> > -int bus_attach_device(struct device * dev)
> > +void bus_attach_device(struct device * dev)
> > {
> > struct bus_type *bus = dev->bus;
> > - int ret = 0;
> > + int ret;
> >
> > if (bus) {
> > dev->is_registered = 1;
> > ret = device_attach(dev);
> > - if (ret >= 0) {
> > + BUG_ON(ret < 0);
> > + if (ret >= 0)
> > klist_add_tail(&dev->knode_bus, &bus->klist_devices);
> > - ret = 0;
> > - } else
> > + else
> > dev->is_registered = 0;
>
> It looks odd to test the value of ret when you've just crashed the system
> if ret < 0. You probably should change the BUG_ON to a WARN_ON or
> something similar.
OK, WARN_ON is probably better (but it should never happen anyway).
Updated patch below.
From: Cornelia Huck <cornelia.huck@de.ibm.com>
Don't fail bus_attach_device() if the device cannot be bound.
If dev->driver has been specified, reset it to NULL if device_bind_driver()
failed and add the device as an unbound device. As a result, bus_attach_device()
now cannot fail, and we can remove some checking from device_add().
Also remove an unneeded check in bus_rescan_devices_helper().
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
drivers/base/base.h | 2 +-
drivers/base/bus.c | 13 +++++--------
drivers/base/core.c | 5 +----
drivers/base/dd.c | 6 +++++-
4 files changed, 12 insertions(+), 14 deletions(-)
--- linux-2.6.orig/drivers/base/dd.c
+++ linux-2.6/drivers/base/dd.c
@@ -221,7 +221,7 @@ static int device_probe_drivers(void *da
*
* Returns 1 if the device was bound to a driver;
* 0 if no matching device was found or multithreaded probing is done;
- * error code otherwise.
+ * -ENODEV if the device is not registered.
*
* When called for a USB interface, @dev->parent->sem must be held.
*/
@@ -235,6 +235,10 @@ int device_attach(struct device * dev)
ret = device_bind_driver(dev);
if (ret == 0)
ret = 1;
+ else {
+ dev->driver = NULL;
+ ret = 0;
+ }
} else {
if (dev->bus->multithread_probe)
probe_task = kthread_run(device_probe_drivers, dev,
--- linux-2.6.orig/drivers/base/core.c
+++ linux-2.6/drivers/base/core.c
@@ -479,8 +479,7 @@ int device_add(struct device *dev)
if ((error = bus_add_device(dev)))
goto BusError;
kobject_uevent(&dev->kobj, KOBJ_ADD);
- if ((error = bus_attach_device(dev)))
- goto AttachError;
+ bus_attach_device(dev);
if (parent)
klist_add_tail(&dev->knode_parent, &parent->klist_children);
@@ -499,8 +498,6 @@ int device_add(struct device *dev)
kfree(class_name);
put_device(dev);
return error;
- AttachError:
- bus_remove_device(dev);
BusError:
device_pm_remove(dev);
PMError:
--- linux-2.6.orig/drivers/base/base.h
+++ linux-2.6/drivers/base/base.h
@@ -16,7 +16,7 @@ extern int cpu_dev_init(void);
extern int attribute_container_init(void);
extern int bus_add_device(struct device * dev);
-extern int bus_attach_device(struct device * dev);
+extern void bus_attach_device(struct device * dev);
extern void bus_remove_device(struct device * dev);
extern struct bus_type *get_bus(struct bus_type * bus);
extern void put_bus(struct bus_type * bus);
--- linux-2.6.orig/drivers/base/bus.c
+++ linux-2.6/drivers/base/bus.c
@@ -406,21 +406,20 @@ out_put:
* - Add device to bus's list of devices.
* - Try to attach to driver.
*/
-int bus_attach_device(struct device * dev)
+void bus_attach_device(struct device * dev)
{
struct bus_type *bus = dev->bus;
- int ret = 0;
+ int ret;
if (bus) {
dev->is_registered = 1;
ret = device_attach(dev);
- if (ret >= 0) {
+ WARN_ON(ret < 0);
+ if (ret >= 0)
klist_add_tail(&dev->knode_bus, &bus->klist_devices);
- ret = 0;
- } else
+ else
dev->is_registered = 0;
}
- return ret;
}
/**
@@ -593,8 +592,6 @@ static int __must_check bus_rescan_devic
ret = device_attach(dev);
if (dev->parent)
up(&dev->parent->sem);
- if (ret > 0)
- ret = 0;
}
return ret < 0 ? ret : 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Patch 4/4] Driver core: Don't fail attaching the device if it cannot be bound.
2006-10-17 16:25 ` Cornelia Huck
@ 2006-10-17 19:43 ` Alan Stern
0 siblings, 0 replies; 4+ messages in thread
From: Alan Stern @ 2006-10-17 19:43 UTC (permalink / raw)
To: Cornelia Huck; +Cc: Greg K-H, Duncan Sands, linux-kernel
On Tue, 17 Oct 2006, Cornelia Huck wrote:
> On Tue, 17 Oct 2006 12:04:28 -0400 (EDT),
> Alan Stern <stern@rowland.harvard.edu> wrote:
> > It looks odd to test the value of ret when you've just crashed the system
> > if ret < 0. You probably should change the BUG_ON to a WARN_ON or
> > something similar.
>
> OK, WARN_ON is probably better (but it should never happen anyway).
> Updated patch below.
Yes, I like this one better.
Alan Stern
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2006-10-17 19:43 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2006-10-17 11:06 [Patch 4/4] Driver core: Don't fail attaching the device if it cannot be bound Cornelia Huck
2006-10-17 16:04 ` Alan Stern
2006-10-17 16:25 ` Cornelia Huck
2006-10-17 19:43 ` Alan Stern
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