diff options
Diffstat (limited to 'drivers/comedi/comedi_fops.c')
| -rw-r--r-- | drivers/comedi/comedi_fops.c | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c index c83fd14dd7ad..23b7178522ae 100644 --- a/drivers/comedi/comedi_fops.c +++ b/drivers/comedi/comedi_fops.c @@ -787,6 +787,7 @@ static int is_device_busy(struct comedi_device *dev) struct comedi_subdevice *s; int i; + lockdep_assert_held_write(&dev->attach_lock); lockdep_assert_held(&dev->mutex); if (!dev->attached) return 0; @@ -795,7 +796,16 @@ static int is_device_busy(struct comedi_device *dev) s = &dev->subdevices[i]; if (s->busy) return 1; - if (s->async && comedi_buf_is_mmapped(s)) + if (!s->async) + continue; + if (comedi_buf_is_mmapped(s)) + return 1; + /* + * There may be tasks still waiting on the subdevice's wait + * queue, although they should already be about to be removed + * from it since the subdevice has no active async command. + */ + if (wq_has_sleeper(&s->async->wait_head)) return 1; } @@ -825,15 +835,22 @@ static int do_devconfig_ioctl(struct comedi_device *dev, return -EPERM; if (!arg) { - if (is_device_busy(dev)) - return -EBUSY; + int rc = 0; + if (dev->attached) { - struct module *driver_module = dev->driver->module; + down_write(&dev->attach_lock); + if (is_device_busy(dev)) { + rc = -EBUSY; + } else { + struct module *driver_module = + dev->driver->module; - comedi_device_detach(dev); - module_put(driver_module); + comedi_device_detach_locked(dev); + module_put(driver_module); + } + up_write(&dev->attach_lock); } - return 0; + return rc; } if (copy_from_user(&it, arg, sizeof(it))) |