On Mon, Aug 07, 2017 at 09:39:53AM -0700, Dave Jiang wrote:
> Adding blk-mq support to the pmem driver in addition to the direct bio
> support.
Can you explain why this is only done for pmem and not btt and nd_blk?
> This allows for hardware offloading via DMA engines. By default
> the bio method will be enabled. The blk-mq support can be turned on via
> module parameter queue_mode=1.
Any way to auto-discovery the right mode? Also I'd actually much
prefer for this to be a separate driver instead of having two entirely
different I/O paths in the same module.
> +struct pmem_cmd {
> + struct request *rq;
> +};
There is no point in having private data that just has a struct
request backpointer. Just pass the request along.
>
> -static void pmem_release_queue(void *q)
> +static void pmem_release_queue(void *data)
> {
> - blk_cleanup_queue(q);
> + struct pmem_device *pmem = (struct pmem_device *)data;
No need for the cast.
> +static int pmem_handle_cmd(struct pmem_cmd *cmd)
Please merge this into the queue_rq handler.
> + struct request *req = cmd->rq;
> + struct request_queue *q = req->q;
> + struct pmem_device *pmem = q->queuedata;
> + struct nd_region *nd_region = to_region(pmem);
> + struct bio_vec bvec;
> + struct req_iterator iter;
> + int rc = 0;
> +
> + if (req->cmd_flags & REQ_FLUSH)
> + nvdimm_flush(nd_region);
For a blk-mq driver you need to check for REQ_OP_FLUSH, .e.g.
switch (req_op(req)) {
case REQ_FLUSH:
ret = nvdimm_flush(nd_region);
break;
case REQ_OP_READ:
ret = pmem_do_io(req, false);
break;
case REQ_OP_WRITE:
ret = pmem_do_io(req, true);
if (req->cmd_flags & REQ_FUA)
nvdimm_flush(nd_region);
break;
default:
ret = BLK_STS_NOTSUPP;
break;
}
> + pmem->tag_set.queue_depth = 64;
Where does this magic number come from?
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