nvme: introduce struct nvme_request

This adds a shared per-request structure for all NVMe I/O.  This structure
is embedded as the first member in all NVMe transport drivers request
private data and allows to implement common functionality between the
drivers.

The first use is to replace the current abuse of the SCSI command
passthrough fields in struct request for the NVMe command passthrough,
but it will grow a field more fields to allow implementing things
like common abort handlers in the future.

The passthrough commands are handled by having a pointer to the SQE
(struct nvme_command) in struct nvme_request, and the union of the
possible result fields, which had to be turned from an anonymous
into a named union for that purpose.  This avoids having to pass
a reference to a full CQE around and thus makes checking the result
a lot more lightweight.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

4 files changed, 18 insertions, 18 deletions

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 6559d5afa7bf..c232552be2d8 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -617,7 +617,7 @@ u16 nvmet_ctrl_find_get(const char *subsysnqn, const char *hostnqn, u16 cntlid,
 	if (!subsys) {
 		pr_warn("connect request for invalid subsystem %s!\n",
 			subsysnqn);
-		req->rsp->result = IPO_IATTR_CONNECT_DATA(subsysnqn);
+		req->rsp->result.u32 = IPO_IATTR_CONNECT_DATA(subsysnqn);
 		return NVME_SC_CONNECT_INVALID_PARAM | NVME_SC_DNR;
 	}
 
@@ -638,7 +638,7 @@ u16 nvmet_ctrl_find_get(const char *subsysnqn, const char *hostnqn, u16 cntlid,
 
 	pr_warn("could not find controller %d for subsys %s / host %s\n",
 		cntlid, subsysnqn, hostnqn);
-	req->rsp->result = IPO_IATTR_CONNECT_DATA(cntlid);
+	req->rsp->result.u32 = IPO_IATTR_CONNECT_DATA(cntlid);
 	status = NVME_SC_CONNECT_INVALID_PARAM | NVME_SC_DNR;
 
 out:
@@ -700,7 +700,7 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 	if (!subsys) {
 		pr_warn("connect request for invalid subsystem %s!\n",
 			subsysnqn);
-		req->rsp->result = IPO_IATTR_CONNECT_DATA(subsysnqn);
+		req->rsp->result.u32 = IPO_IATTR_CONNECT_DATA(subsysnqn);
 		goto out;
 	}
 
@@ -709,7 +709,7 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 	if (!nvmet_host_allowed(req, subsys, hostnqn)) {
 		pr_info("connect by host %s for subsystem %s not allowed\n",
 			hostnqn, subsysnqn);
-		req->rsp->result = IPO_IATTR_CONNECT_DATA(hostnqn);
+		req->rsp->result.u32 = IPO_IATTR_CONNECT_DATA(hostnqn);
 		up_read(&nvmet_config_sem);
 		goto out_put_subsystem;
 	}
diff --git a/drivers/nvme/target/fabrics-cmd.c b/drivers/nvme/target/fabrics-cmd.c
index 9a97ae67e656..f4088198cd0d 100644
--- a/drivers/nvme/target/fabrics-cmd.c
+++ b/drivers/nvme/target/fabrics-cmd.c
@@ -69,7 +69,7 @@ static void nvmet_execute_prop_get(struct nvmet_req *req)
 		}
 	}
 
-	req->rsp->result64 = cpu_to_le64(val);
+	req->rsp->result.u64 = cpu_to_le64(val);
 	nvmet_req_complete(req, status);
 }
 
@@ -125,7 +125,7 @@ static void nvmet_execute_admin_connect(struct nvmet_req *req)
 	d = kmap(sg_page(req->sg)) + req->sg->offset;
 
 	/* zero out initial completion result, assign values as needed */
-	req->rsp->result = 0;
+	req->rsp->result.u32 = 0;
 
 	if (c->recfmt != 0) {
 		pr_warn("invalid connect version (%d).\n",
@@ -138,7 +138,7 @@ static void nvmet_execute_admin_connect(struct nvmet_req *req)
 		pr_warn("connect attempt for invalid controller ID %#x\n",
 			d->cntlid);
 		status = NVME_SC_CONNECT_INVALID_PARAM | NVME_SC_DNR;
-		req->rsp->result = IPO_IATTR_CONNECT_DATA(cntlid);
+		req->rsp->result.u32 = IPO_IATTR_CONNECT_DATA(cntlid);
 		goto out;
 	}
 
@@ -155,7 +155,7 @@ static void nvmet_execute_admin_connect(struct nvmet_req *req)
 
 	pr_info("creating controller %d for NQN %s.\n",
 			ctrl->cntlid, ctrl->hostnqn);
-	req->rsp->result16 = cpu_to_le16(ctrl->cntlid);
+	req->rsp->result.u16 = cpu_to_le16(ctrl->cntlid);
 
 out:
 	kunmap(sg_page(req->sg));
@@ -173,7 +173,7 @@ static void nvmet_execute_io_connect(struct nvmet_req *req)
 	d = kmap(sg_page(req->sg)) + req->sg->offset;
 
 	/* zero out initial completion result, assign values as needed */
-	req->rsp->result = 0;
+	req->rsp->result.u32 = 0;
 
 	if (c->recfmt != 0) {
 		pr_warn("invalid connect version (%d).\n",
@@ -191,14 +191,14 @@ static void nvmet_execute_io_connect(struct nvmet_req *req)
 	if (unlikely(qid > ctrl->subsys->max_qid)) {
 		pr_warn("invalid queue id (%d)\n", qid);
 		status = NVME_SC_CONNECT_INVALID_PARAM | NVME_SC_DNR;
-		req->rsp->result = IPO_IATTR_CONNECT_SQE(qid);
+		req->rsp->result.u32 = IPO_IATTR_CONNECT_SQE(qid);
 		goto out_ctrl_put;
 	}
 
 	status = nvmet_install_queue(ctrl, req);
 	if (status) {
 		/* pass back cntlid that had the issue of installing queue */
-		req->rsp->result16 = cpu_to_le16(ctrl->cntlid);
+		req->rsp->result.u16 = cpu_to_le16(ctrl->cntlid);
 		goto out_ctrl_put;
 	}
 
diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
index d5df77d686b2..757e21a31128 100644
--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -36,6 +36,7 @@
 	(NVME_LOOP_AQ_DEPTH - NVME_LOOP_NR_AEN_COMMANDS)
 
 struct nvme_loop_iod {
+	struct nvme_request	nvme_req;
 	struct nvme_command	cmd;
 	struct nvme_completion	rsp;
 	struct nvmet_req	req;
@@ -112,10 +113,10 @@ static void nvme_loop_complete_rq(struct request *req)
 	blk_mq_end_request(req, error);
 }
 
-static void nvme_loop_queue_response(struct nvmet_req *nvme_req)
+static void nvme_loop_queue_response(struct nvmet_req *req)
 {
 	struct nvme_loop_iod *iod =
-		container_of(nvme_req, struct nvme_loop_iod, req);
+		container_of(req, struct nvme_loop_iod, req);
 	struct nvme_completion *cqe = &iod->rsp;
 
 	/*
@@ -128,11 +129,10 @@ static void nvme_loop_queue_response(struct nvmet_req *nvme_req)
 			cqe->command_id >= NVME_LOOP_AQ_BLKMQ_DEPTH)) {
 		nvme_complete_async_event(&iod->queue->ctrl->ctrl, cqe);
 	} else {
-		struct request *req = blk_mq_rq_from_pdu(iod);
+		struct request *rq = blk_mq_rq_from_pdu(iod);
 
-		if (req->cmd_type == REQ_TYPE_DRV_PRIV && req->special)
-			memcpy(req->special, cqe, sizeof(*cqe));
-		blk_mq_complete_request(req, le16_to_cpu(cqe->status) >> 1);
+		iod->nvme_req.result = cqe->result;
+		blk_mq_complete_request(rq, le16_to_cpu(cqe->status) >> 1);
 	}
 }
 
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 76b6eedccaf9..f9c76441e8c9 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -238,7 +238,7 @@ static inline void nvmet_set_status(struct nvmet_req *req, u16 status)
 
 static inline void nvmet_set_result(struct nvmet_req *req, u32 result)
 {
-	req->rsp->result = cpu_to_le32(result);
+	req->rsp->result.u32 = cpu_to_le32(result);
 }
 
 /*