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>

1 files changed, 7 insertions, 24 deletions

diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
index f5e3011e31fc..442f67774ea9 100644
--- a/drivers/nvme/host/lightnvm.c
+++ b/drivers/nvme/host/lightnvm.c
@@ -146,14 +146,6 @@ struct nvme_nvm_command {
 	};
 };
 
-struct nvme_nvm_completion {
-	__le64	result;		/* Used by LightNVM to return ppa completions */
-	__le16	sq_head;	/* how much of this queue may be reclaimed */
-	__le16	sq_id;		/* submission queue that generated this entry */
-	__u16	command_id;	/* of the command which completed */
-	__le16	status;		/* did the command fail, and if so, why? */
-};
-
 #define NVME_NVM_LP_MLC_PAIRS 886
 struct nvme_nvm_lp_mlc {
 	__le16			num_pairs;
@@ -481,11 +473,8 @@ static inline void nvme_nvm_rqtocmd(struct request *rq, struct nvm_rq *rqd,
 static void nvme_nvm_end_io(struct request *rq, int error)
 {
 	struct nvm_rq *rqd = rq->end_io_data;
-	struct nvme_nvm_completion *cqe = rq->special;
-
-	if (cqe)
-		rqd->ppa_status = le64_to_cpu(cqe->result);
 
+	rqd->ppa_status = nvme_req(rq)->result.u64;
 	nvm_end_io(rqd, error);
 
 	kfree(rq->cmd);
@@ -500,20 +489,18 @@ static int nvme_nvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
 	struct bio *bio = rqd->bio;
 	struct nvme_nvm_command *cmd;
 
-	rq = blk_mq_alloc_request(q, bio_data_dir(bio), 0);
-	if (IS_ERR(rq))
+	cmd = kzalloc(sizeof(struct nvme_nvm_command), GFP_KERNEL);
+	if (!cmd)
 		return -ENOMEM;
 
-	cmd = kzalloc(sizeof(struct nvme_nvm_command) +
-				sizeof(struct nvme_nvm_completion), GFP_KERNEL);
-	if (!cmd) {
-		blk_mq_free_request(rq);
+	rq = nvme_alloc_request(q, (struct nvme_command *)cmd, 0, NVME_QID_ANY);
+	if (IS_ERR(rq)) {
+		kfree(cmd);
 		return -ENOMEM;
 	}
+	rq->cmd_flags &= ~REQ_FAILFAST_DRIVER;
 
-	rq->cmd_type = REQ_TYPE_DRV_PRIV;
 	rq->ioprio = bio_prio(bio);
-
 	if (bio_has_data(bio))
 		rq->nr_phys_segments = bio_phys_segments(q, bio);
 
@@ -522,10 +509,6 @@ static int nvme_nvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
 
 	nvme_nvm_rqtocmd(rq, rqd, ns, cmd);
 
-	rq->cmd = (unsigned char *)cmd;
-	rq->cmd_len = sizeof(struct nvme_nvm_command);
-	rq->special = cmd + 1;
-
 	rq->end_io_data = rqd;
 
 	blk_execute_rq_nowait(q, NULL, rq, 0, nvme_nvm_end_io);