Staging: comedi: COMEDI_BUFINFO with no async - report no bytes read or written

When the COMEDI_BUFINFO ioctl is used on a subdevice without
asynchronous streaming command support, set 'bytes_read = 0' and
'bytes_written = 0' in the buffer info returned back to the user.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 39ed22b80229..75256251250d 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -584,6 +584,8 @@ static int do_bufinfo_ioctl(struct comedi_device *dev,
                 bi.buf_read_ptr = 0;
                 bi.buf_write_count = 0;
                 bi.buf_read_count = 0;
+                bi.bytes_read = 0;
+                bi.bytes_written = 0;
                 goto copyback;
         }