From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1949296AbcBSQOO (ORCPT ); Fri, 19 Feb 2016 11:14:14 -0500 Received: from smtp73.iad3a.emailsrvr.com ([173.203.187.73]:43546 "EHLO smtp73.iad3a.emailsrvr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1949132AbcBSQOK (ORCPT ); Fri, 19 Feb 2016 11:14:10 -0500 X-Auth-ID: abbotti@mev.co.uk X-Sender-Id: abbotti@mev.co.uk From: Ian Abbott To: devel@driverdev.osuosl.org Cc: Greg Kroah-Hartman , Ian Abbott , H Hartley Sweeten , linux-kernel@vger.kernel.org Subject: [PATCH 3/8] staging: comedi: COMEDI_BUFINFO: update buffer before becoming non-busy Date: Fri, 19 Feb 2016 16:13:52 +0000 Message-Id: <1455898437-4640-4-git-send-email-abbotti@mev.co.uk> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1455898437-4640-1-git-send-email-abbotti@mev.co.uk> References: <1455898437-4640-1-git-send-email-abbotti@mev.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The `COMEDI_BUFINFO` ioctl is used to advance the current position in the buffer by a specified amount (which can be 0) and get the new position. For an asynchronous command in the "read" direction, if the command has finished acquiring data normally, `do_become_nonbusy()` is called to terminate the command. That resets the buffer position, and currently, the position information returned back to the user is after the buffer has been reset. It should be more useful to return the buffer position before the reset, so move the call to `do_become_nonbusy()` after the code that gets the updated buffer position. Signed-off-by: Ian Abbott --- drivers/staging/comedi/comedi_fops.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 04d6040..e625ef2 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1111,6 +1111,7 @@ static int do_bufinfo_ioctl(struct comedi_device *dev, struct comedi_bufinfo bi; struct comedi_subdevice *s; struct comedi_async *async; + bool become_nonbusy = false; if (copy_from_user(&bi, arg, sizeof(bi))) return -EFAULT; @@ -1149,7 +1150,7 @@ static int do_bufinfo_ioctl(struct comedi_device *dev, if (comedi_is_subdevice_idle(s) && comedi_buf_read_n_available(s) == 0) - do_become_nonbusy(dev, s); + become_nonbusy = true; } bi.bytes_written = 0; } else { @@ -1168,6 +1169,9 @@ copyback_position: bi.buf_read_count = async->buf_read_count; bi.buf_read_ptr = async->buf_read_ptr; + if (become_nonbusy) + do_become_nonbusy(dev, s); + copyback: if (copy_to_user(arg, &bi, sizeof(bi))) return -EFAULT; -- 2.7.0