diff options
| -rw-r--r-- | drivers/staging/comedi/comedi_fops.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 4b9d8f00328..ee33cba59a4 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1577,7 +1577,7 @@ static unsigned int comedi_poll(struct file *file, poll_table * wait) mask = 0; read_subdev = comedi_get_read_subdevice(dev_file_info); - if (read_subdev) { + if (read_subdev && read_subdev->async) { poll_wait(file, &read_subdev->async->wait_head, wait); if (!read_subdev->busy || comedi_buf_read_n_available(read_subdev->async) > 0 @@ -1587,7 +1587,7 @@ static unsigned int comedi_poll(struct file *file, poll_table * wait) } } write_subdev = comedi_get_write_subdevice(dev_file_info); - if (write_subdev) { + if (write_subdev && write_subdev->async) { poll_wait(file, &write_subdev->async->wait_head, wait); comedi_buf_write_alloc(write_subdev->async, write_subdev->async->prealloc_bufsz); @@ -1629,7 +1629,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf, } s = comedi_get_write_subdevice(dev_file_info); - if (s == NULL) { + if (s == NULL || s->async == NULL) { retval = -EIO; goto done; } @@ -1740,7 +1740,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes, } s = comedi_get_read_subdevice(dev_file_info); - if (s == NULL) { + if (s == NULL || s->async == NULL) { retval = -EIO; goto done; } |