staging: comedi: fix comedi_nsamples_left.

commit a42ae5905140c324362fe5036ae1dbb16e4d359c upstream.

A rounding error was causing comedi_nsamples_left to
return the wrong value when nsamples was not a multiple
of the scan length.

Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Frank Mori Hess <fmh6jj@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index a5bf2cc..1736248 100644 (file)
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -484,8 +484,7 @@ unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
        struct comedi_cmd *cmd = &async->cmd;
 
        if (cmd->stop_src == TRIG_COUNT) {
-               unsigned int nscans = nsamples / cmd->scan_end_arg;
-               unsigned int scans_left = __comedi_nscans_left(s, nscans);
+               unsigned int scans_left = __comedi_nscans_left(s, cmd->stop_arg);
                unsigned int scan_pos =
                    comedi_bytes_to_samples(s, async->scan_progress);
                unsigned long long samples_left = 0;