On 21/02/2017 09:33, Cheah Kok Cheong wrote:
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 ]
Snippet 2 looks fine. Alternatives are to modify Snippet 1 to split the
initialization of the pointer variable after the '=', or to shorten the
the name of the 'chan' variable.
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Web: http://www.mev.co.uk/ )=-
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