Re: [PATCH] staging: comedi: shortened a long line

[Joe Perches]

On Sat, 2018-06-09 at 12:54 +0200, Chris Opperman wrote:
> Shortened a long line to improve readability in 
> drivers/staging/comedi/drivers.c

Hi Chris.

Look at the whole function and see if you can
find a better way to write it instead of merely
doing what a brainless tool like checkpatch asks.

> diff --git a/drivers/staging/comedi/drivers.c 
> b/drivers/staging/comedi/drivers.c
[]
> @@ -475,7 +475,8 @@ unsigned int comedi_nsamples_left(struct comedi_subdevice 
> *s,
>       struct comedi_cmd *cmd = &async->cmd;
>  
>       if (cmd->stop_src == TRIG_COUNT) {
> -             unsigned int scans_left = __comedi_nscans_left(s, 
> cmd->stop_arg);
> +             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;

For instance, this is the existing function:

unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
                                  unsigned int nsamples)
{
        struct comedi_async *async = s->async;
        struct comedi_cmd *cmd = &async->cmd;

        if (cmd->stop_src == TRIG_COUNT) {
                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;

                if (scans_left) {
                        samples_left = ((unsigned long long)scans_left *
                                        cmd->scan_end_arg) - scan_pos;
                }

                if (samples_left < nsamples)
                        nsamples = samples_left;
        }
        return nsamples;
}
EXPORT_SYMBOL_GPL(comedi_nsamples_left);

By using multiple returns and removing indentation,
this could become something that doesn't fits
neatly on 80 columns.
It's the same number of vertical lines too.

unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
                                  unsigned int nsamples)
{
        struct comedi_async *async = s->async;
        struct comedi_cmd *cmd = &async->cmd;
        unsigned int scans_left;
        u64 samples_left;

        if (cmd->stop_src != TRIG_COUNT)
                return nsamples;

        scans_left = __comedi_nscans_left(s, cmd->stop_arg);
        if (scans_left == 0)
                return 0;

        samples_left = (u64)scans_left * cmd->scan_end_arg -
                        comedi_bytes_to_samples(s, s->async->scan_progress);
        if (samples_left < nsamples)
                return samples_left;

        return nsamples;
}
EXPORT_SYMBOL_GPL(comedi_nsamples_left);

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