Re: [PATCH] driver-core : get_device before create/remove sysfsfiles

From: Cornelia Huck
Date: Wed Jan 30 2008 - 05:33:29 EST


On Wed, 30 Jan 2008 09:56:25 +0800,
Dave Young <hidave.darkstar@xxxxxxxxx> wrote:

> get dev reference before create/remove sysfiles, errno fixes as well.
>
> Signed-off-by: Dave Young <hidave.darkstar@xxxxxxxxx>
>
> ---
> drivers/base/core.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff -upr a/drivers/base/core.c b/drivers/base/core.c
> --- a/drivers/base/core.c 2008-01-30 09:49:56.000000000 +0800
> +++ b/drivers/base/core.c 2008-01-30 09:49:56.000000000 +0800
> @@ -414,7 +414,7 @@ struct kset *devices_kset;
> */
> int device_create_file(struct device *dev, struct device_attribute *attr)
> {
> - int error = 0;
> + int error = -ENODEV;

Uhm... why?

> if (get_device(dev)) {
> error = sysfs_create_file(&dev->kobj, &attr->attr);
> put_device(dev);
> @@ -442,9 +442,11 @@ void device_remove_file(struct device *d
> */
> int device_create_bin_file(struct device *dev, struct bin_attribute *attr)
> {
> - int error = -EINVAL;
> - if (dev)
> + int error = -ENODEV;
> + if (get_device(dev)) {
> error = sysfs_create_bin_file(&dev->kobj, attr);
> + put_device(dev);
> + }

Why do we need to grab a reference here? If the calling site doesn't
hold unto a reference already, something is seriously broken.

> return error;
> }
> EXPORT_SYMBOL_GPL(device_create_bin_file);
> @@ -456,8 +458,10 @@ EXPORT_SYMBOL_GPL(device_create_bin_file
> */
> void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
> {
> - if (dev)
> + if (get_device(dev)) {
> sysfs_remove_bin_file(&dev->kobj, attr);
> + put_device(dev);
> + }

Dito.

> }
> EXPORT_SYMBOL_GPL(device_remove_bin_file);
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