diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2013-02-01 13:23:20 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-02-04 01:44:20 (GMT) |
| commit | de06d7c6b8e3b886eec0302ecbadf76944a42ca4 (patch) | |
| tree | da56c9e3aadd7278b9ddde550f09db348f4bcc11 | |
| parent | da71751177f35f0ca5494968cc237511c423a744 (diff) | |
| download | linux-de06d7c6b8e3b886eec0302ecbadf76944a42ca4.tar.xz | |
staging: comedi: restrict comedi_set_hw_dev() usage
Don't allow comedi drivers to change `dev->hw_dev` using
`comedi_set_hw_dev()` if it's already been set. Return `-EEXIST` in
that case.
`dev->hw_dev` needs to be set to NULL by the core during clean-up of the
comedi device, so add a local function `comedi_clear_hw_dev()` to do
that.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/comedi/drivers.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c index 5adf9fc..d91b173 100644 --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -45,14 +45,21 @@ struct comedi_driver *comedi_drivers; int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev) { - struct device *old_hw_dev = dev->hw_dev; - + if (hw_dev == dev->hw_dev) + return 0; + if (dev->hw_dev != NULL) + return -EEXIST; dev->hw_dev = get_device(hw_dev); - put_device(old_hw_dev); return 0; } EXPORT_SYMBOL_GPL(comedi_set_hw_dev); +static void comedi_clear_hw_dev(struct comedi_device *dev) +{ + put_device(dev->hw_dev); + dev->hw_dev = NULL; +} + int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices) { struct comedi_subdevice *s; @@ -108,7 +115,7 @@ static void cleanup_device(struct comedi_device *dev) dev->write_subdev = NULL; dev->open = NULL; dev->close = NULL; - comedi_set_hw_dev(dev, NULL); + comedi_clear_hw_dev(dev); } static void __comedi_device_detach(struct comedi_device *dev) |