alinux: nvme-pci: Improve mapping single segment requests using PRP

fix #29327388

Now the blk-mq did not support multi-page bvec, which means each bvec
can only contain one page. For simple PRP, it just support one bvec
in the bio though the physical segment is only 1, otherwise it can
not map the whole request.

In future if we support multi-page bvecs, this patch can be dropped.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>

drivers/nvme/host/pci.c

@@ -852,8 +852,9 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 
 	if (blk_rq_nr_phys_segments(req) == 1) {
 		struct bio_vec bv = req_bvec(req);
+		unsigned int bio_pages = bio_pages_all(req->bio);
 
-		if (bv.bv_offset + bv.bv_len <= dev->ctrl.page_size * 2)
+		if (bio_pages == 1 && bv.bv_offset + bv.bv_len <= dev->ctrl.page_size * 2)
 			return nvme_setup_prp_simple(dev, req,
 						     &cmnd->rw, &bv);