[dm-devel] [RFC PATCH] blk-core: remove blk_put_request()

[Christoph Hellwig]

On Wed, Feb 24, 2021 at 09:48:21AM -0700, Jens Axboe wrote:
> Would make sense to rename blk_get_request() to blk_mq_alloc_request()
> and then we have API symmetry. The get/put don't make sense when there
> are no references involved.
> 
> But it's a lot of churn for very little reward, which is always kind
> of annoying. Especially for the person that has to carry the patches.

Let's do the following:

 - move the initialize_rq_fn call from blk_get_request into
   blk_mq_alloc_request and make the former a trivial alias for the
   latter
 - migrate to the blk_mq_* versions on a per-driver/subsystem basis.
   The scsi migration depends on the first item above, so it will have
   to go with that or wait for the next merge window
 - don't migrate the legacy ide driver, as it is about to be removed and
   has a huge number of blk_get_request calls