Re: [PATCH v3 2/3] btrfs: remove btrfs_bio_alloc() helper

David Sterba
2021-09-20T12:41:40Z

On Mon, Sep 20, 2021 at 06:33:14PM +0800, Qu Wenruo wrote:
>
>
> On 2021/9/17 20:49, Nikolay Borisov wrote:
> >
> >
> > On 17.09.21 г. 15:43, David Sterba wrote:
> >> So should we add another helper that takes the exact number and drop the
> >> parameter everwhere is 0 so it's just btrfs_io_bio_alloc() with the
> >> fallback?
> >
> > But by adding another helper we just introduce more indirection.
> >
> > Actually I'd argue that if 0 is a sane default then BIO_MAX_VECS cannot
> > be any worse because:
> >
> > a) It's a number which is as good as 0
> > b) It's even named. So this is technically better than a plain 0
> >
>
> Any final call on this?
>
> I hope this could be an example for future optional parameters.
>
> We have some existing codes using two different inline functions, and
> both of them call a internal but exported function with "__" prefix.
>
> We also have call sites passing all needed parameters just like Nikolay
> suggested.

I'm fine with explicitly using BIO_MAX_VECS instead of 0. I'll update it
in the patch, no need to resend.