> + if (dio->flags & IOMAP_DIO_DEFER_COMP) {
> + /* only polled IO cares about private cleared */
> + iocb->private = dio;
FYI, I find this comment a bit weird as it comments on what we're
not doing in a path where it is irreleant. I'd rather only clear
the private data in the path where polling is applicable and have
a comment there why it is cleared. That probably belongs into the
first patch restructuring the function.
> @@ -277,12 +308,15 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter,
> * data IO that doesn't require any metadata updates (including
> * after IO completion such as unwritten extent conversion) and
> * the underlying device supports FUA. This allows us to avoid
> - * cache flushes on IO completion.
> + * cache flushes on IO completion. If we can't use FUA and
> + * need to sync, disable in-task completions.
... because iomap_dio_complete will have to call generic_write_sync to
do a blocking ->fsync call.
> @@ -308,6 +342,8 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter,
> pad = pos & (fs_block_size - 1);
> if (pad)
> iomap_dio_zero(iter, dio, pos - pad, pad);
> +
> + dio->flags &= ~IOMAP_DIO_DEFER_COMP;
Why does zeroing disable the deferred completions? I can't really think
of why, which is probably a strong indicator why this needs a comment.
