lightnvm: implement generic path for sync I/O

Implement a generic path for sending sync I/O on LightNVM. This allows
to reuse the standard synchronous path trough blk_execute_rq(), instead
of implementing a wait_for_completion on the target side (e.g., pblk).

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 56 insertions, 14 deletions

diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
index 6017153c2439..8fc949c5b49b 100644
--- a/drivers/nvme/host/lightnvm.c
+++ b/drivers/nvme/host/lightnvm.c
@@ -492,34 +492,47 @@ static void nvme_nvm_end_io(struct request *rq, blk_status_t status)
 	blk_mq_free_request(rq);
 }
 
-static int nvme_nvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
+static struct request *nvme_nvm_alloc_request(struct request_queue *q,
+					      struct nvm_rq *rqd,
+					      struct nvme_nvm_command *cmd)
 {
-	struct request_queue *q = dev->q;
 	struct nvme_ns *ns = q->queuedata;
 	struct request *rq;
-	struct bio *bio = rqd->bio;
-	struct nvme_nvm_command *cmd;
-
-	cmd = kzalloc(sizeof(struct nvme_nvm_command), GFP_KERNEL);
-	if (!cmd)
-		return -ENOMEM;
 
 	nvme_nvm_rqtocmd(rqd, ns, cmd);
 
 	rq = nvme_alloc_request(q, (struct nvme_command *)cmd, 0, NVME_QID_ANY);
-	if (IS_ERR(rq)) {
-		kfree(cmd);
-		return PTR_ERR(rq);
-	}
+	if (IS_ERR(rq))
+		return rq;
+
 	rq->cmd_flags &= ~REQ_FAILFAST_DRIVER;
 
-	if (bio) {
-		blk_init_request_from_bio(rq, bio);
+	if (rqd->bio) {
+		blk_init_request_from_bio(rq, rqd->bio);
 	} else {
 		rq->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM);
 		rq->__data_len = 0;
 	}
 
+	return rq;
+}
+
+static int nvme_nvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
+{
+	struct request_queue *q = dev->q;
+	struct nvme_nvm_command *cmd;
+	struct request *rq;
+
+	cmd = kzalloc(sizeof(struct nvme_nvm_command), GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	rq = nvme_nvm_alloc_request(q, rqd, cmd);
+	if (IS_ERR(rq)) {
+		kfree(cmd);
+		return PTR_ERR(rq);
+	}
+
 	rq->end_io_data = rqd;
 
 	blk_execute_rq_nowait(q, NULL, rq, 0, nvme_nvm_end_io);
@@ -527,6 +540,34 @@ static int nvme_nvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
 	return 0;
 }
 
+static int nvme_nvm_submit_io_sync(struct nvm_dev *dev, struct nvm_rq *rqd)
+{
+	struct request_queue *q = dev->q;
+	struct request *rq;
+	struct nvme_nvm_command cmd;
+	int ret = 0;
+
+	memset(&cmd, 0, sizeof(struct nvme_nvm_command));
+
+	rq = nvme_nvm_alloc_request(q, rqd, &cmd);
+	if (IS_ERR(rq))
+		return PTR_ERR(rq);
+
+	/* I/Os can fail and the error is signaled through rqd. Callers must
+	 * handle the error accordingly.
+	 */
+	blk_execute_rq(q, NULL, rq, 0);
+	if (nvme_req(rq)->flags & NVME_REQ_CANCELLED)
+		ret = -EINTR;
+
+	rqd->ppa_status = le64_to_cpu(nvme_req(rq)->result.u64);
+	rqd->error = nvme_req(rq)->status;
+
+	blk_mq_free_request(rq);
+
+	return ret;
+}
+
 static void *nvme_nvm_create_dma_pool(struct nvm_dev *nvmdev, char *name)
 {
 	struct nvme_ns *ns = nvmdev->q->queuedata;
@@ -562,6 +603,7 @@ static struct nvm_dev_ops nvme_nvm_dev_ops = {
 	.set_bb_tbl		= nvme_nvm_set_bb_tbl,
 
 	.submit_io		= nvme_nvm_submit_io,
+	.submit_io_sync		= nvme_nvm_submit_io_sync,
 
 	.create_dma_pool	= nvme_nvm_create_dma_pool,
 	.destroy_dma_pool	= nvme_nvm_destroy_dma_pool,