Re: [PATCH 11/11] block: don't check for BIO_MAX_PAGES in blk_bio_segment_split()

From: Christoph Hellwig
Date: Fri Apr 21 2017 - 07:34:20 EST


On Thu, Apr 20, 2017 at 03:38:50PM +1000, NeilBrown wrote:
> blk_bio_segment_split() makes sure bios have no more than
> BIO_MAX_PAGES entries in the bi_io_vec.
> This was done because bio_clone_bioset() (when given a
> mempool bioset) could not handle larger io_vecs.
>
> No driver uses bio_clone_bioset() any more, they all
> use bio_clone_fast() if anything, and bio_clone_fast()
> doesn't clone the bi_io_vec.

Hmm. From Jens tree:

drivers/lightnvm/pblk-read.c: int_bio = bio_clone_bioset(bio, GFP_KERNEL, fs_bio_set);
drivers/md/raid1.c: mbio = bio_clone_bioset_partial(bio, GFP_NOIO,
drivers/md/raid1.c: mbio = bio_clone_bioset_partial(bio, GFP_NOIO,

I did not see your series touching either of those. They probably
don't matter for the code removed as the bios are controlled by the
drivers, but the changelog still seems odd.