diff options
| -rw-r--r-- | drivers/staging/comedi/comedi_fops.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index c9da6f39b1c6..94c23484284f 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2420,10 +2420,15 @@ static ssize_t comedi_write(struct file *file, const char __user *buf, * sufficient (unless there have been 2**32 detaches in the * meantime!), but check the subdevice pointer as well just in * case. + * + * Also check the subdevice is still in a suitable state to + * become non-busy in case it changed behind our back. */ new_s = comedi_file_write_subdevice(file); if (dev->attached && old_detach_count == dev->detach_count && - s == new_s && new_s->async == async) + s == new_s && new_s->async == async && s->busy == file && + (async->cmd.flags & CMDF_WRITE) && + !comedi_is_subdevice_running(s)) do_become_nonbusy(dev, s); mutex_unlock(&dev->mutex); } |