nvme: return the whole CQE through the request passthrough interface

When LightNVM send asynchronous data commands, it would need to allocate extra memory for cqe. Would it make sense to pass cqe directly and assume that it is live through the blk_mq_complete_request call?

Both LighNVM and NVMe over Fabrics need to look at more than just the status and result field.

Signed-off-by Christoph Hellwig <hch at lst.de>

Reviewed-by Sagi Grimberg <sagig at mellanox.com>

Reviewed-by Jay Freyensee <james.p.freyensee at intel.com>

Signed-off-by Sagi Grimberg <sagig at mellanox.com>

---
 drivers/nvme/host/core.c | 27 +++++++++++++++++++--------
 drivers/nvme/host/nvme.h |  3 ++-
 drivers/nvme/host/pci.c  | 10 +++-------
 3 files changed, 24 insertions(+), 16 deletions(-)

drivers/nvme/host/core.c +19 -8

index c326931..6715bbf 100644
@@ -107,7 +107,6 @@ struct request *nvme_alloc_request(struct request_queue *q,
 
 	req->cmd = (unsigned char *)cmd;
 	req->cmd_len = sizeof(struct nvme_command);
-	req->special = (void *)0;
 
 	return req;
 }

@@ -117,7 +116,8 @@ struct request *nvme_alloc_request(struct request_queue *q,
  * if the result is positive, it's an NVM Express status code
  */
 int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
-		void *buffer, unsigned bufflen, u32 *result, unsigned timeout)
+		struct nvme_completion *cqe, void *buffer, unsigned bufflen,
+		unsigned timeout)
 {
 	struct request *req;
 	int ret;

@@ -127,6 +127,7 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		return PTR_ERR(req);
 
 	req->timeout = timeout ? timeout : ADMIN_TIMEOUT;
+	req->special = cqe;
 
 	if (buffer && bufflen) {
 		ret = blk_rq_map_kern(q, req, buffer, bufflen, GFP_KERNEL);

@@ -135,8 +136,6 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 	}
 
 	blk_execute_rq(req->q, NULL, req, 0);
-	if (result)
-		*result = (u32)(uintptr_t)req->special;
 	ret = req->errors;
  out:
 	blk_mq_free_request(req);

@@ -146,7 +145,7 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		void *buffer, unsigned bufflen)
 {
-	return __nvme_submit_sync_cmd(q, cmd, buffer, bufflen, NULL, 0);
+	return __nvme_submit_sync_cmd(q, cmd, NULL, buffer, bufflen, 0);
 }
 
 int __nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,

@@ -155,6 +154,7 @@ int __nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
 		u32 *result, unsigned timeout)
 {
 	bool write = cmd->common.opcode & 1;
+	struct nvme_completion cqe;
 	struct nvme_ns *ns = q->queuedata;
 	struct gendisk *disk = ns ? ns->disk : NULL;
 	struct request *req;

@@ -167,6 +167,7 @@ int __nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
 		return PTR_ERR(req);
 
 	req->timeout = timeout ? timeout : ADMIN_TIMEOUT;
+	req->special = &cqe;
 
 	if (ubuffer && bufflen) {
 		ret = blk_rq_map_user(q, req, NULL, ubuffer, bufflen,

@@ -221,7 +222,7 @@ int __nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
 	blk_execute_rq(req->q, disk, req, 0);
 	ret = req->errors;
 	if (result)
-		*result = (u32)(uintptr_t)req->special;
+		*result = le32_to_cpu(cqe.result);
 	if (meta && !ret && !write) {
 		if (copy_to_user(meta_buffer, meta, meta_len))
 			ret = -EFAULT;

@@ -302,6 +303,8 @@ int nvme_get_features(struct nvme_ctrl *dev, unsigned fid, unsigned nsid,
 					dma_addr_t dma_addr, u32 *result)
 {
 	struct nvme_command c;
+	struct nvme_completion cqe;
+	int ret;
 
 	memset(&c, 0, sizeof(c));
 	c.features.opcode = nvme_admin_get_features;

@@ -309,13 +312,18 @@ int nvme_get_features(struct nvme_ctrl *dev, unsigned fid, unsigned nsid,
 	c.features.prp1 = cpu_to_le64(dma_addr);
 	c.features.fid = cpu_to_le32(fid);
 
-	return __nvme_submit_sync_cmd(dev->admin_q, &c, NULL, 0, result, 0);
+	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &cqe, NULL, 0, 0);
+	if (ret >= 0)
+		*result = le32_to_cpu(cqe.result);
+	return ret;
 }
 
 int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword11,
 					dma_addr_t dma_addr, u32 *result)
 {
 	struct nvme_command c;
+	struct nvme_completion cqe;
+	int ret;
 
 	memset(&c, 0, sizeof(c));
 	c.features.opcode = nvme_admin_set_features;

@@ -323,7 +331,10 @@ int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword11,
 	c.features.fid = cpu_to_le32(fid);
 	c.features.dword11 = cpu_to_le32(dword11);
 
-	return __nvme_submit_sync_cmd(dev->admin_q, &c, NULL, 0, result, 0);
+	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &cqe, NULL, 0, 0);
+	if (ret >= 0)
+		*result = le32_to_cpu(cqe.result);
+	return ret;
 }
 
 int nvme_get_log_page(struct nvme_ctrl *dev, struct nvme_smart_log **log)

drivers/nvme/host/nvme.h +2 -1

index 4fb5bb7..d85997f 100644
@@ -247,7 +247,8 @@ void nvme_requeue_req(struct request *req);
 int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		void *buf, unsigned bufflen);
 int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
-		void *buffer, unsigned bufflen,  u32 *result, unsigned timeout);
+		struct nvme_completion *cqe, void *buffer, unsigned bufflen,
+		unsigned timeout);
 int nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
 		void __user *ubuffer, unsigned bufflen, u32 *result,
 		unsigned timeout);

drivers/nvme/host/pci.c +2 -4

index 72ef832..f8ae20c 100644
@@ -759,10 +759,8 @@ static void __nvme_process_cq(struct nvme_queue *nvmeq, unsigned int *tag)
 		}
 
 		req = blk_mq_tag_to_rq(*nvmeq->tags, cqe.command_id);
-		if (req->cmd_type == REQ_TYPE_DRV_PRIV) {
-			u32 result = le32_to_cpu(cqe.result);
-			req->special = (void *)(uintptr_t)result;
-		}
+		if (req->cmd_type == REQ_TYPE_DRV_PRIV && req->special)
+			memcpy(req->special, &cqe, sizeof(cqe));
 		blk_mq_complete_request(req, status >> 1);
 
 	}

@@ -905,12 +903,10 @@ static void abort_endio(struct request *req, int error)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 	struct nvme_queue *nvmeq = iod->nvmeq;