nvme: move command clear into the various setup helpers

We don't have to worry about doing extra memsets by moving it outside
the protection of RQF_DONTPREP, as nvme doesn't do partial completions.

This is in preparation for making the read/write fast path not do a full
memset of the command.
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/nvme/host/core.c

@@ -834,6 +834,7 @@ static void nvme_assign_write_stream(struct nvme_ctrl *ctrl,
 static inline void nvme_setup_flush(struct nvme_ns *ns,
 		struct nvme_command *cmnd)
 {
+	memset(cmnd, 0, sizeof(*cmnd));
 	cmnd->common.opcode = nvme_cmd_flush;
 	cmnd->common.nsid = cpu_to_le32(ns->head->ns_id);
 }
@@ -885,6 +886,7 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
 		return BLK_STS_IOERR;
 	}
 
+	memset(cmnd, 0, sizeof(*cmnd));
 	cmnd->dsm.opcode = nvme_cmd_dsm;
 	cmnd->dsm.nsid = cpu_to_le32(ns->head->ns_id);
 	cmnd->dsm.nr = cpu_to_le32(segments - 1);
@@ -901,6 +903,8 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
 static inline blk_status_t nvme_setup_write_zeroes(struct nvme_ns *ns,
 		struct request *req, struct nvme_command *cmnd)
 {
+	memset(cmnd, 0, sizeof(*cmnd));
+
 	if (ns->ctrl->quirks & NVME_QUIRK_DEALLOCATE_ZEROES)
 		return nvme_setup_discard(ns, req, cmnd);
 
@@ -925,6 +929,8 @@ static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
 	u16 control = 0;
 	u32 dsmgmt = 0;
 
+	memset(cmnd, 0, sizeof(*cmnd));
+
 	if (req->cmd_flags & REQ_FUA)
 		control |= NVME_RW_FUA;
 	if (req->cmd_flags & (REQ_FAILFAST_DEV | REQ_RAHEAD))
@@ -993,10 +999,8 @@ blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req)
 	struct nvme_ctrl *ctrl = nvme_req(req)->ctrl;
 	blk_status_t ret = BLK_STS_OK;
 
-	if (!(req->rq_flags & RQF_DONTPREP)) {
+	if (!(req->rq_flags & RQF_DONTPREP))
 		nvme_clear_nvme_request(req);
-		memset(cmd, 0, sizeof(*cmd));
-	}
 
 	switch (req_op(req)) {
 	case REQ_OP_DRV_IN:

drivers/nvme/host/zns.c

@@ -233,6 +233,8 @@ int nvme_ns_report_zones(struct nvme_ns *ns, sector_t sector,
 blk_status_t nvme_setup_zone_mgmt_send(struct nvme_ns *ns, struct request *req,
 		struct nvme_command *c, enum nvme_zone_mgmt_action action)
 {
+	memset(c, 0, sizeof(*c));
+
 	c->zms.opcode = nvme_cmd_zone_mgmt_send;
 	c->zms.nsid = cpu_to_le32(ns->head->ns_id);
 	c->zms.slba = cpu_to_le64(nvme_sect_to_lba(ns, blk_rq_pos(req)));