On Fri, May 26, 2017 at 11:56:30PM +0000, Bart Van Assche wrote: > I have tried to move that call into blk_mq_alloc_request() but that > resulted in a kernel oops during boot due to scsi_add_cmd_to_list() > dereferencing scsi_cmnd.device and due to that pointer being invalid. > I think that pointer was invalid because moving the initialize_rq_fn() > call into blk_mq_alloc_request() caused request initialization to be > skipped for the following code path: > submit_bio() > -> generic_make_request() > -> .make_request_fn == blk_mq_make_request() > -> blk_mq_sched_get_request() > -> __blk_mq_alloc_request() > -> blk_mq_rq_ctx_init() > > This is why I would like to keep the .initialize_rq_fn() call in > blk_mq_rq_ctx_init(). But we don't call scsi_req_init for this path either with the current code. So not having the call should be fine as long as you ensure we still manually initialize everything for the non-passthrough path in the later patches. I'll keep an eye on that issue while reviewing the remaining patches.
