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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Frank Mori Hess <fmh6jj@gmail.com>,
        Ian Abbott <abbotti@mev.co.uk>
Subject: [PATCH 4.9 76/86] staging: comedi: fix comedi_nsamples_left.
Date:   Fri, 16 Mar 2018 16:23:39 +0100
Message-Id: <20180316152322.466885794@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

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;