[PATCH 1/5] nvme-pci: remove nvme_queue from nvme_iod

[Keith Busch <kbusch@fb.com>]

From: Keith Busch <kbusch@kernel.org>

We can get the nvme_queue from the req just as easily, so save some
space by removing the duplicate pointer to the same structure.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 drivers/nvme/host/pci.c | 28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 644664098ae7..138d408f7306 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -226,7 +226,6 @@ struct nvme_queue {
 struct nvme_iod {
 	struct nvme_request req;
 	struct nvme_command cmd;
-	struct nvme_queue *nvmeq;
 	bool use_sgl;
 	int aborted;
 	int npages;		/* In the PRP list. 0 means small pool in use */
@@ -431,11 +430,6 @@ static int nvme_pci_init_request(struct blk_mq_tag_set *set,
 {
 	struct nvme_dev *dev = set->driver_data;
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-	int queue_idx = (set == &dev->tagset) ? hctx_idx + 1 : 0;
-	struct nvme_queue *nvmeq = &dev->queues[queue_idx];
-
-	BUG_ON(!nvmeq);
-	iod->nvmeq = nvmeq;
 
 	nvme_req(req)->ctrl = &dev->ctrl;
 	nvme_req(req)->cmd = &iod->cmd;
@@ -529,7 +523,7 @@ static void **nvme_pci_iod_list(struct request *req)
 
 static inline bool nvme_pci_use_sgls(struct nvme_dev *dev, struct request *req)
 {
-	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
 	int nseg = blk_rq_nr_phys_segments(req);
 	unsigned int avg_seg_size;
 
@@ -537,7 +531,7 @@ static inline bool nvme_pci_use_sgls(struct nvme_dev *dev, struct request *req)
 
 	if (!nvme_ctrl_sgl_supported(&dev->ctrl))
 		return false;
-	if (!iod->nvmeq->qid)
+	if (!nvmeq->qid)
 		return false;
 	if (!sgl_threshold || avg_seg_size < sgl_threshold)
 		return false;
@@ -843,6 +837,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 	int nr_mapped;
 
 	if (blk_rq_nr_phys_segments(req) == 1) {
+		struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
 		struct bio_vec bv = req_bvec(req);
 
 		if (!is_pci_p2pdma_page(bv.bv_page)) {
@@ -850,7 +845,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 				return nvme_setup_prp_simple(dev, req,
 							     &cmnd->rw, &bv);
 
-			if (iod->nvmeq->qid && sgl_threshold &&
+			if (nvmeq->qid && sgl_threshold &&
 			    nvme_ctrl_sgl_supported(&dev->ctrl))
 				return nvme_setup_sgl_simple(dev, req,
 							     &cmnd->rw, &bv);
@@ -1030,12 +1025,16 @@ static void nvme_queue_rqs(struct request **rqlist)
 
 static __always_inline void nvme_pci_unmap_rq(struct request *req)
 {
-	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-	struct nvme_dev *dev = iod->nvmeq->dev;
+	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
+	struct nvme_dev *dev = nvmeq->dev;
+
+	if (blk_integrity_rq(req)) {
+	        struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 
-	if (blk_integrity_rq(req))
 		dma_unmap_page(dev->dev, iod->meta_dma,
 			       rq_integrity_vec(req)->bv_len, rq_data_dir(req));
+	}
+
 	if (blk_rq_nr_phys_segments(req))
 		nvme_unmap_data(dev, req);
 }
@@ -1283,8 +1282,7 @@ static int adapter_delete_sq(struct nvme_dev *dev, u16 sqid)
 
 static void abort_endio(struct request *req, blk_status_t error)
 {
-	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-	struct nvme_queue *nvmeq = iod->nvmeq;
+	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
 
 	dev_warn(nvmeq->dev->ctrl.device,
 		 "Abort status: 0x%x", nvme_req(req)->status);
@@ -1346,7 +1344,7 @@ static void nvme_warn_reset(struct nvme_dev *dev, u32 csts)
 static enum blk_eh_timer_return nvme_timeout(struct request *req)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-	struct nvme_queue *nvmeq = iod->nvmeq;
+	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
 	struct nvme_dev *dev = nvmeq->dev;
 	struct request *abort_req;
 	struct nvme_command cmd = { };
-- 
2.30.2