Re: [PATCH v3 2/4] iomap: lift zeroed mapping handling into iomap_zero_range()

[Christoph Hellwig <hch@infradead.org>]

On Fri, Nov 08, 2024 at 07:42:44AM -0500, Brian Foster wrote:
> In preparation for special handling of subranges, lift the zeroed
> mapping logic from the iterator into the caller.

What's that special code?  I don't really see anything added to this
in the new code?  In general I would prefer if all code for the
iteration would be kept in a single function in preparation for
unrolling these loops.  If you want to keep this code separate
from the write zeroes logic (which seems like a good idea) please
just just move the actual real zeroing out of iomap_zero_iter into
a separate helper similar to how we e.g. have multiple different
implementations in the dio iterator.

> +	while ((ret = iomap_iter(&iter, ops)) > 0) {
> +		const struct iomap *s = iomap_iter_srcmap(&iter);
> +
> +		if (s->type == IOMAP_HOLE || s->type == IOMAP_UNWRITTEN) {
> +			loff_t p = iomap_length(&iter);

Also please stick to variable names that are readable and preferably
the same as in the surrounding code, e.g. s -> srcmap p -> pos.