Re: [PATCH RFC] allow bio code to unmap sg io requests and have blk_execute_rq_nowait bounce bios

[Mike Christie <michaelc@cs.wisc.edu>]

Mike Christie wrote:
> And, as I work on the adding of BLKERR_* error values in replacement
> of the dm-multupath/bio sense patch, I was thinking about your comment
> about having one true make_request function. It seems like if we extended
> bios to handle more request stuff (like what is needed for SG IO) we could
> just pass the bio to __make_request - with some modifications to __make_request -
> instead of doing it request based and moving the blk_queue_bounce call to
> blk_execute_rq_nowait  like I did in my patch. Is this what you were thinking when
> adding the bio sense code?

I mean doing things like sg io and dm-multipath HW handler's manual
failover with bios instead of requests could simplify those things, but
I am guessing bios were not meant to handle some of the lower level
details like SCSI things. Or maybe they are or should be done in a more
generic way?