struct comedi_device *comedi_open(const char *filename)
{
- struct comedi_device *dev;
+ struct comedi_device *dev, *retval = NULL;
unsigned int minor;
if (strncmp(filename, "/dev/comedi", 11) != 0)
if (minor >= COMEDI_NUM_BOARD_MINORS)
return NULL;
- dev = comedi_dev_from_minor(minor);
-
- if (!dev || !dev->attached)
+ dev = comedi_dev_get_from_minor(minor);
+ if (!dev)
return NULL;
- if (!try_module_get(dev->driver->module))
- return NULL;
+ down_read(&dev->attach_lock);
+ if (dev->attached)
+ retval = dev;
+ else
+ retval = NULL;
+ up_read(&dev->attach_lock);
+
+ if (retval == NULL)
+ comedi_dev_put(dev);
- return dev;
+ return retval;
}
EXPORT_SYMBOL_GPL(comedi_open);
-int comedi_close(struct comedi_device *d)
+int comedi_close(struct comedi_device *dev)
{
- struct comedi_device *dev = (struct comedi_device *)d;
-
- module_put(dev->driver->module);
-
+ comedi_dev_put(dev);
return 0;
}
EXPORT_SYMBOL_GPL(comedi_close);
unsigned int *data)
{
struct comedi_subdevice *s;
- int ret = 0;
+ int ret;
+
+ mutex_lock(&dev->mutex);
+
+ if (!dev->attached) {
+ ret = -EINVAL;
+ goto error;
+ }
/* a subdevice instruction */
if (insn->subdev >= dev->n_subdevices) {
s->busy = NULL;
error:
+ mutex_unlock(&dev->mutex);
return ret;
}
unsigned int shift;
int ret;
- if (subdev >= dev->n_subdevices)
- return -EINVAL;
-
base_channel = CR_CHAN(base_channel);
n_chan = comedi_get_n_channels(dev, subdev);
if (base_channel >= n_chan)
unsigned int subd)
{
struct comedi_subdevice *s;
-
- if (subd > dev->n_subdevices)
- return -ENODEV;
-
- for (; subd < dev->n_subdevices; subd++) {
- s = &dev->subdevices[subd];
- if (s->type == type)
- return subd;
- }
- return -1;
+ int ret = -ENODEV;
+
+ down_read(&dev->attach_lock);
+ if (dev->attached)
+ for (; subd < dev->n_subdevices; subd++) {
+ s = &dev->subdevices[subd];
+ if (s->type == type) {
+ ret = subd;
+ break;
+ }
+ }
+ up_read(&dev->attach_lock);
+ return ret;
}
EXPORT_SYMBOL_GPL(comedi_find_subdevice_by_type);
int comedi_get_n_channels(struct comedi_device *dev, unsigned int subdevice)
{
- struct comedi_subdevice *s = &dev->subdevices[subdevice];
+ int n;
+
+ down_read(&dev->attach_lock);
+ if (!dev->attached || subdevice >= dev->n_subdevices)
+ n = 0;
+ else
+ n = dev->subdevices[subdevice].n_chan;
+ up_read(&dev->attach_lock);
- return s->n_chan;
+ return n;
}
EXPORT_SYMBOL_GPL(comedi_get_n_channels);