linux-kernel - Re: [PATCH 2/2] block: Rework bio_for_each_folio

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Message-ID: <ZCr1/K03uGF3neCY@moria.home.lan>
Date:   Mon, 3 Apr 2023 11:51:24 -0400
From:   Kent Overstreet <kent.overstreet@...ux.dev>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        willy@...radead.org, axboe@...nel.dk
Subject: Re: [PATCH 2/2] block: Rework bio_for_each_folio_all()

On Mon, Apr 03, 2023 at 08:13:21AM -0700, Christoph Hellwig wrote:
> On Mon, Mar 27, 2023 at 01:44:02PM -0400, Kent Overstreet wrote:
> > +	bio_for_each_folio_all(fv, bio, iter)
> > +		iomap_finish_folio_read(fv.fv_folio, fv.fv_offset, fv.fv_len, error);
> 
> Please avoid the overly long lines.  Also if we pass all arguments
> of the folio_vec we might as ell just pass that folio_vec anyway.
> 
> > -	BUG_ON(iter->idx > bio->bi_vcnt || (iter->idx == bio->bi_vcnt && iter->done));
> > +	BUG_ON(iter->idx > bio->bi_vcnt ||
> > +	       (iter->idx == bio->bi_vcnt && iter->done));
> 
> Seems like this should be folded into the previous patch.  Also I
> generally prefer to avoid top-level || in asserts and just do multiple
> asserts, as that shows which condition triggered.

It should be folded in, but it's logically the same assert (advance
past the end of the iter) so not worth the increased code size.