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, 13 insertions, 15 deletions

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index ef34f2f3566a..2fd632bcd975 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -221,8 +221,7 @@ struct request *nvme_alloc_request(struct request_queue *q,
 
 	req->cmd_type = REQ_TYPE_DRV_PRIV;
 	req->cmd_flags |= REQ_FAILFAST_DRIVER;
-	req->cmd = (unsigned char *)cmd;
-	req->cmd_len = sizeof(struct nvme_command);
+	nvme_req(req)->cmd = cmd;
 
 	return req;
 }
@@ -321,7 +320,7 @@ int nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
 	int ret = 0;
 
 	if (req->cmd_type == REQ_TYPE_DRV_PRIV)
-		memcpy(cmd, req->cmd, sizeof(*cmd));
+		memcpy(cmd, nvme_req(req)->cmd, sizeof(*cmd));
 	else if (req_op(req) == REQ_OP_FLUSH)
 		nvme_setup_flush(ns, cmd);
 	else if (req_op(req) == REQ_OP_DISCARD)
@@ -338,7 +337,7 @@ EXPORT_SYMBOL_GPL(nvme_setup_cmd);
  * 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,
-		struct nvme_completion *cqe, void *buffer, unsigned bufflen,
+		union nvme_result *result, void *buffer, unsigned bufflen,
 		unsigned timeout, int qid, int at_head, int flags)
 {
 	struct request *req;
@@ -349,7 +348,6 @@ 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);
@@ -358,6 +356,8 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 	}
 
 	blk_execute_rq(req->q, NULL, req, at_head);
+	if (result)
+		*result = nvme_req(req)->result;
 	ret = req->errors;
  out:
 	blk_mq_free_request(req);
@@ -379,7 +379,6 @@ int __nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
 		u32 *result, unsigned timeout)
 {
 	bool write = nvme_is_write(cmd);
-	struct nvme_completion cqe;
 	struct nvme_ns *ns = q->queuedata;
 	struct gendisk *disk = ns ? ns->disk : NULL;
 	struct request *req;
@@ -392,7 +391,6 @@ 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,
@@ -447,7 +445,7 @@ 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 = le32_to_cpu(cqe.result);
+		*result = le32_to_cpu(nvme_req(req)->result.u32);
 	if (meta && !ret && !write) {
 		if (copy_to_user(meta_buffer, meta, meta_len))
 			ret = -EFAULT;
@@ -596,7 +594,7 @@ int nvme_get_features(struct nvme_ctrl *dev, unsigned fid, unsigned nsid,
 		      void *buffer, size_t buflen, u32 *result)
 {
 	struct nvme_command c;
-	struct nvme_completion cqe;
+	union nvme_result res;
 	int ret;
 
 	memset(&c, 0, sizeof(c));
@@ -604,10 +602,10 @@ int nvme_get_features(struct nvme_ctrl *dev, unsigned fid, unsigned nsid,
 	c.features.nsid = cpu_to_le32(nsid);
 	c.features.fid = cpu_to_le32(fid);
 
-	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &cqe, buffer, buflen, 0,
+	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &res, buffer, buflen, 0,
 			NVME_QID_ANY, 0, 0);
 	if (ret >= 0 && result)
-		*result = le32_to_cpu(cqe.result);
+		*result = le32_to_cpu(res.u32);
 	return ret;
 }
 
@@ -615,7 +613,7 @@ int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword11,
 		      void *buffer, size_t buflen, u32 *result)
 {
 	struct nvme_command c;
-	struct nvme_completion cqe;
+	union nvme_result res;
 	int ret;
 
 	memset(&c, 0, sizeof(c));
@@ -623,10 +621,10 @@ 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);
 
-	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &cqe,
+	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &res,
 			buffer, buflen, 0, NVME_QID_ANY, 0, 0);
 	if (ret >= 0 && result)
-		*result = le32_to_cpu(cqe.result);
+		*result = le32_to_cpu(res.u32);
 	return ret;
 }
 
@@ -1901,7 +1899,7 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl,
 		struct nvme_completion *cqe)
 {
 	u16 status = le16_to_cpu(cqe->status) >> 1;
-	u32 result = le32_to_cpu(cqe->result);
+	u32 result = le32_to_cpu(cqe->result.u32);
 
 	if (status == NVME_SC_SUCCESS || status == NVME_SC_ABORT_REQ) {
 		++ctrl->event_limit;