Re: [PATCH v2 4/5] btrfs: introduce btrfs_bio_for_each_block_all() helper

[David Sterba <dsterba@suse.cz>]

On Sat, Sep 06, 2025 at 07:38:27AM +0930, Qu Wenruo wrote:
> >> +static inline struct bvec_iter init_bvec_iter_for_bio(struct bio *bio)
> >> +{
> >> +	struct bio_vec *bvec;
> >> +	u32 bio_size = 0;
> >> +	int i;
> >> +
> >> +	bio_for_each_bvec_all(bvec, bio, i)
> >> +		bio_size += bvec->bv_len;
> >> +
> >> +	return (struct bvec_iter) {
> >> +		.bi_sector = 0,
> >> +		.bi_size = bio_size,
> >> +		.bi_idx = 0,
> >> +		.bi_bvec_done = 0,
> >> +	};
> > 
> > We don't use this kind of initializers, usually the structure is passed
> > as parameter, but I can see how it makes it convenient in the for()
> > initialization. The parameter way would work but would also look strange
> > so I think it's acceptable.
> 
> I'd say this really makes a lot of things easier, and avoid pointer 
> usage (in this particular case it allows us to use local @iter without 
> the need of a caller provided pointer), it should get more usage.

If the patterns are an improvement (and this means for the people who
work on the code) then we can do it, also because the minimum version of
compilers is increasing over time which means newer C features are
available. This one in particular is not new and looks readable, so ok
for me.