[PATCH for-next v8 3/5] nvme: refactor nvme_alloc_user_request

[Kanchan Joshi]

>> +	if (ret)
>> +		goto out;
>> +	bio = req->bio;
>
>I think we can also do away with this bio local variable now.
>
>> +	if (bdev)
>> +		bio_set_dev(bio, bdev);
>
>We don't need the bio_set_dev here as mentioned last time, so I think
>we should remove it in a prep patch.

we miss completing polled io with this change.
bdev needs to be put in bio to complete polled passthrough IO.
nvme_ns_chr_uring_cmd_iopoll uses bio_poll and that in turn makes use of
this.