On Mon, Feb 20, 2017 at 05:36:52PM +0000, Ian Abbott wrote:
> On 20/02/17 16:02, Cheah Kok Cheong wrote:
> >On Mon, Feb 20, 2017 at 10:03:39AM +0000, Ian Abbott wrote:
> >>On 20/02/17 08:28, Cheah Kok Cheong wrote:
> >>>Fix checkpatch warning "Avoid multiple line dereference"
> >>>using a local variable to avoid line wrap.
> >>>
> >>>Signed-off-by: Cheah Kok Cheong <thrust73@xxxxxxxxx>
> >>>---
> >>>drivers/staging/comedi/drivers/comedi_test.c | 6 ++----
> >>>1 file changed, 2 insertions(+), 4 deletions(-)
> >>>
> >>>diff --git a/drivers/staging/comedi/drivers/comedi_test.c b/drivers/staging/comedi/drivers/comedi_test.c
> >>>index 2a063f0..fde83e0 100644
> >>>--- a/drivers/staging/comedi/drivers/comedi_test.c
> >>>+++ b/drivers/staging/comedi/drivers/comedi_test.c
> >>>@@ -480,11 +480,9 @@ static void waveform_ao_timer(unsigned long arg)
> >>> /* output the last scan */
> >>> for (i = 0; i < cmd->scan_end_arg; i++) {
> >>> unsigned int chan = CR_CHAN(cmd->chanlist[i]);
> >>>+ unsigned short d = devpriv->ao_loopbacks[chan];
> >>>
> >>>- if (comedi_buf_read_samples(s,
> >>>- &devpriv->
> >>>- ao_loopbacks[chan],
> >>>- 1) == 0) {
> >>>+ if (!comedi_buf_read_samples(s, &d, 1)) {
> >>> /* unexpected underrun! (cancelled?) */
> >>> async->events |= COMEDI_CB_OVERFLOW;
> >>> goto underrun;
> >>>
> >>
> >>NAK. This leaves devpriv->ao_loopbacks[chan] unchanged.
> >>
> >
> >Thanks for pointing this out. In that case will assigning the variable to
> >devpriv->ao_loopbacks[chan] be acceptable? Please review below snippet.
> >
> >Otherwise I'll just drop the variable and adjust the lines to avoid
> >checkpatch warning.
> >
> >Sorry for the inconvenience caused.
> >
> >[ Snip ]
> >
> > /* output the last scan */
> > for (i = 0; i < cmd->scan_end_arg; i++) {
> > unsigned int chan = CR_CHAN(cmd->chanlist[i]);
> > unsigned short data;
> >
> > if (!comedi_buf_read_samples(s, &data, 1)) {
> > /* unexpected underrun! (cancelled?) */
> > async->events |= COMEDI_CB_OVERFLOW;
> > goto underrun;
> > }
> >
> > devpriv->ao_loopbacks[chan] = data;
> > }
> > /* advance time of last scan */
> >
> >[ Snip ]
>
> It will work, but you could just use a pointer variable set to
> &devpriv->ao_loopbacks[chan] and pass that to comedi_buf_read_samples().
>
Thanks for the suggestion. I tried below snippet 1 with the shortest pointer
name but 80 characters is exceeded. The declaration and initialisation
will have to be splitted. Will this be acceptable or am I doing it wrong
again?
Sorry for the trouble.
Snippet 1:
[ Snip ]
/* output the last scan */
for (i = 0; i < cmd->scan_end_arg; i++) {
unsigned int chan = CR_CHAN(cmd->chanlist[i]);
unsigned short *p = &devpriv->ao_loopbacks[chan];
if (!comedi_buf_read_samples(s, p, 1)) {
/* unexpected underrun! (cancelled?) */
async->events |= COMEDI_CB_OVERFLOW;
goto underrun;
}
}
/* advance time of last scan */
[ Snip ]
Snippet 2:
[ Snip ]
/* output the last scan */
for (i = 0; i < cmd->scan_end_arg; i++) {
unsigned int chan = CR_CHAN(cmd->chanlist[i]);
unsigned short *pd;
pd = &devpriv->ao_loopbacks[chan];
if (!comedi_buf_read_samples(s, pd, 1)) {
/* unexpected underrun! (cancelled?) */
async->events |= COMEDI_CB_OVERFLOW;
goto underrun;
}
}
[ Snip ]
Thks.
Brgds,
CheahKC
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