[dm-devel] [PATCH V11 14/19] block: handle non-cluster bio out of blk_bio_segment_split

[Christoph Hellwig]

On Wed, Nov 21, 2018 at 11:37:27PM +0800, Ming Lei wrote:
> > +	bio = bio_alloc_bioset(GFP_NOIO, bio_segments(*bio_orig),
> > +			&non_cluster_bio_set);
> 
> bio_segments(*bio_orig) may be > 256, so bio_alloc_bioset() may fail.

Nothing a little min with BIO_MAX_PAGES couldn't fix.  This patch
was just intended as an idea how I think this code could work.