[PATCH for-next v4 3/4] block: add helper to map bvec iterator for passthrough

[Christoph Hellwig]

On Tue, Sep 06, 2022 at 12:03:29PM +0530, Kanchan Joshi wrote:
>> This context looks weird?  That bio_alloc_bioset should not be there,
>> as biosets are only used for file system I/O, which this is not.
>
> if you think it's a deal-breaker, maybe I can add a new bioset in nvme and
> pass that as argument to this helper. Would you prefer that over the
> current approach.

The whole point is that biosets exist to allow for forward progress
guarantees required for file system I/O.  For passthrough I/O
bio_kmalloc is perfectly fine and much simpler.  Adding yet another
bio_set just makes things even worse.