Re: [PATCH v2] block: make sure big bio is splitted into at most 256 bvecs

[Christoph Hellwig]

On Fri, Jun 10, 2016 at 01:37:17PM +0200, Hannes Reinecke wrote:
> Hmm. So everybody is suffering because someone _might_ be using bio_clone?
> Why can't we fixup bio_clone() (or the callers of which) to correctly
> set the queue limits?

The only one suffering is bcache.  Everyone else uses bios below the
block layer arbitrary max size.  The fixup to allow bio_clone support
a larger size is the same one as to allow everyone else submitting
larger bios:  increase BIO_MAX_PAGES and create the required mempools
to back that new larger size.  Or just go for multipage biovecs..