Re: [PATCH] Staging: comedi: drivers: comedi_test: Avoid multiple line dereference

[Cheah Kok Cheong]

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 <thrus...@gmail.com>
> >---
> > 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 ]

Thks.
Brgds,
CheahKC