[PATCH 4.15 012/128] staging: comedi: fix comedi_nsamples_left.

Greg Kroah-Hartman
2018-03-16T15:39:28Z

From: Frank Mori Hess <fmh6jj@gmail.com>

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>

---
drivers/staging/comedi/drivers.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -484,8 +484,7 @@ unsigned int comedi_nsamples_left(struct
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;