From de06d7c6b8e3b886eec0302ecbadf76944a42ca4 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Fri, 1 Feb 2013 13:23:20 +0000 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers.c | 15 +++++++++++---- 1 file 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) -- 2.7.4