staging: comedi: check s->async for poll(), read() and write()
[pandora-kernel.git] / drivers / staging / comedi / comedi_fops.c
index 13e79a1..a023f52 100644 (file)
@@ -1574,7 +1574,7 @@ static unsigned int comedi_poll(struct file *file, poll_table * wait)
 
        mask = 0;
        read_subdev = comedi_get_read_subdevice(dev_file_info);
 
        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
                poll_wait(file, &read_subdev->async->wait_head, wait);
                if (!read_subdev->busy
                    || comedi_buf_read_n_available(read_subdev->async) > 0
@@ -1584,7 +1584,7 @@ static unsigned int comedi_poll(struct file *file, poll_table * wait)
                }
        }
        write_subdev = comedi_get_write_subdevice(dev_file_info);
                }
        }
        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);
                poll_wait(file, &write_subdev->async->wait_head, wait);
                comedi_buf_write_alloc(write_subdev->async,
                                       write_subdev->async->prealloc_bufsz);
@@ -1626,7 +1626,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
        }
 
        s = comedi_get_write_subdevice(dev_file_info);
        }
 
        s = comedi_get_write_subdevice(dev_file_info);
-       if (s == NULL) {
+       if (s == NULL || s->async == NULL) {
                retval = -EIO;
                goto done;
        }
                retval = -EIO;
                goto done;
        }
@@ -1737,7 +1737,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
        }
 
        s = comedi_get_read_subdevice(dev_file_info);
        }
 
        s = comedi_get_read_subdevice(dev_file_info);
-       if (s == NULL) {
+       if (s == NULL || s->async == NULL) {
                retval = -EIO;
                goto done;
        }
                retval = -EIO;
                goto done;
        }