On Wed, Feb 19, 2025 at 12:50:39PM -0500, Brian Foster wrote:
> iomap buffered read advances the iter via iter.processed. To
> continue separating iter advance from return status, update
> iomap_readpage_iter() to advance the iter instead of returning the
> number of bytes processed. In turn, drop the offset parameter and
> sample the updated iter->pos at the start of the function. Update
> the callers to loop based on remaining length in the current
> iteration instead of number of bytes processed.
>
> Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/iomap/buffered-io.c | 45 +++++++++++++++++++-----------------------
> 1 file changed, 20 insertions(+), 25 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index ec227b45f3aa..215866ba264d 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -366,15 +366,14 @@ static inline bool iomap_block_needs_zeroing(const struct iomap_iter *iter,
> pos >= i_size_read(iter->inode);
> }
>
> -static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
> - struct iomap_readpage_ctx *ctx, loff_t offset)
> +static loff_t iomap_readpage_iter(struct iomap_iter *iter,
I wonder, do we really need to return loff_t from some of these
functions now? I thought the only return codes were the -EIO/0 from
iomap_iter_advance?
--D
> + struct iomap_readpage_ctx *ctx)
> {
> const struct iomap *iomap = &iter->iomap;
> - loff_t pos = iter->pos + offset;
> - loff_t length = iomap_length(iter) - offset;
> + loff_t pos = iter->pos;
> + loff_t length = iomap_length(iter);
> struct folio *folio = ctx->cur_folio;
> struct iomap_folio_state *ifs;
> - loff_t orig_pos = pos;
> size_t poff, plen;
> sector_t sector;
>
> @@ -438,25 +437,22 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
> * we can skip trailing ones as they will be handled in the next
> * iteration.
> */
> - return pos - orig_pos + plen;
> + length = pos - iter->pos + plen;
> + return iomap_iter_advance(iter, &length);
> }
>
> -static loff_t iomap_read_folio_iter(const struct iomap_iter *iter,
> +static loff_t iomap_read_folio_iter(struct iomap_iter *iter,
> struct iomap_readpage_ctx *ctx)
> {
> - struct folio *folio = ctx->cur_folio;
> - size_t offset = offset_in_folio(folio, iter->pos);
> - loff_t length = min_t(loff_t, folio_size(folio) - offset,
> - iomap_length(iter));
> - loff_t done, ret;
> -
> - for (done = 0; done < length; done += ret) {
> - ret = iomap_readpage_iter(iter, ctx, done);
> - if (ret <= 0)
> + loff_t ret;
> +
> + while (iomap_length(iter)) {
> + ret = iomap_readpage_iter(iter, ctx);
> + if (ret)
> return ret;
> }
>
> - return done;
> + return 0;
> }
>
> int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
> @@ -493,15 +489,14 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
> }
> EXPORT_SYMBOL_GPL(iomap_read_folio);
>
> -static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
> +static loff_t iomap_readahead_iter(struct iomap_iter *iter,
> struct iomap_readpage_ctx *ctx)
> {
> - loff_t length = iomap_length(iter);
> - loff_t done, ret;
> + loff_t ret;
>
> - for (done = 0; done < length; done += ret) {
> + while (iomap_length(iter)) {
> if (ctx->cur_folio &&
> - offset_in_folio(ctx->cur_folio, iter->pos + done) == 0) {
> + offset_in_folio(ctx->cur_folio, iter->pos) == 0) {
> if (!ctx->cur_folio_in_bio)
> folio_unlock(ctx->cur_folio);
> ctx->cur_folio = NULL;
> @@ -510,12 +505,12 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
> ctx->cur_folio = readahead_folio(ctx->rac);
> ctx->cur_folio_in_bio = false;
> }
> - ret = iomap_readpage_iter(iter, ctx, done);
> - if (ret <= 0)
> + ret = iomap_readpage_iter(iter, ctx);
> + if (ret)
> return ret;
> }
>
> - return done;
> + return 0;
> }
>
> /**
> --
> 2.48.1
>
>
