Re: [PATCH v4 07/23] ata: libahci_platform: Convert to using devm bulk clocks API

Serge Semin
2022-06-17T19:54:11Z

On Thu, Jun 16, 2022 at 09:23:28AM +0900, Damien Le Moal wrote:
> On 2022/06/16 5:45, Serge Semin wrote:
> [...]
> >>> + hpriv->clks = devm_kzalloc(dev, sizeof(*hpriv->clks), GFP_KERNEL);
> >>> + if (!hpriv->clks) {
> >>> + rc = -ENOMEM;
> >>> + goto err_out;
> >>> + }
> >>> + hpriv->clks->clk = devm_clk_get_optional(dev, NULL);
> >
> >>> + if (IS_ERR(hpriv->clks->clk)) {
> >>> + rc = PTR_ERR(hpriv->clks->clk);
> >>> + goto err_out;
> >>> + } else if (hpriv->clks->clk) {
> >>
> >> Nit: the else is not needed here.
> >
> > Well, it depends on what you see behind it. I see many reasons to keep
> > it and only one tiny reason to drop it. Keeping it will improve the
> > code readability and maintainability like having a more natural
> > execution flow representation, thus clearer read-flow (else part as
> > exception to the if part), less modifications should the goto part is
> > changed/removed, a more exact program flow representation can be used
> > by the compiler for some internal optimizations, it's one line shorter
> > than the case we no 'else' here. On the other hand indeed we can drop
> > it since if the conditional statement is true, the code afterwards
> > won't be executed due to the goto operator. But as I see it dropping
> > the else operator won't improve anything, but vise-versa will worsen
> > the code instead. So if I get to miss something please justify why you
> > want it being dropped, otherwise I would rather preserve it.
>
> An else after a goto or return is never necessary and in my opinion makes the
> code harder to read. I am not interested in debating this in general anyway. For
> this particular case, the code would be:
>
> hpriv->clks->clk = devm_clk_get_optional(dev, NULL);
> if (IS_ERR(hpriv->clks->clk)) {
> /* Error path */
> rc = PTR_ERR(hpriv->clks->clk);
> goto err_out;
> }
>
> /* Normal path */
> if (hpriv->clks->clk) {
> ...
> }
>
> Which in my opinion is a lot easier to understand compared to having to parse
> the if/else if and figure out which case in that sequence is normal vs error.
>

> As noted, this is a nit. If you really insist, keep that else if.

Ok. I'll leave it as is then.

Thanks
-Sergey

>
> >
> > -Sergey
> >
> >>
> >>> + hpriv->clks->id = __clk_get_name(hpriv->clks->clk);
> >>> + hpriv->n_clks = 1;
> >>> }
> >>> - hpriv->clks[i] = clk;
> >>> }
> >>>
> >>> hpriv->ahci_regulator = devm_regulator_get(dev, "ahci");
> >>
> >>
> >> --
> >> Damien Le Moal
> >> Western Digital Research
>
>
> --
> Damien Le Moal
> Western Digital Research