[PATCH v3 10/17] nvmet: Do not require SGL for PCI target controller commands

[Damien Le Moal]

Support for SGL is optional for the PCI transport. Modify
nvmet_req_init() to not require the NVME_CMD_SGL_METABUF command flag to
be set if the target controller transport type is NVMF_TRTYPE_PCI.
In addition to this, the NVMe base specification v2.1 mandate that all
admin commands use PRP, that is, have CDW0.PSDT cleared to 0. Modify
nvmet_parse_admin_cmd() to check this.

Finally, modify nvmet_check_transfer_len() and
nvmet_check_data_len_lte() to return the appropriate error status
depending on the command using SGL or PRP. Since for fabrics
nvmet_req_init() checks that a command uses SGL, always, this change
affects only PCI target controllers.

Signed-off-by: Damien Le Moal <dlemoal at kernel.org>
---
 drivers/nvme/target/admin-cmd.c |  5 +++++
 drivers/nvme/target/core.c      | 27 +++++++++++++++++++++------
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index c91864c185fc..0c5127a1d191 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -1478,6 +1478,11 @@ u16 nvmet_parse_admin_cmd(struct nvmet_req *req)
 	if (unlikely(ret))
 		return ret;
 
+	/* For PCI controllers, admin commands shall not use SGL. */
+	if (nvmet_is_pci_ctrl(req->sq->ctrl) && !req->sq->qid &&
+	    cmd->common.flags & NVME_CMD_SGL_ALL)
+		return NVME_SC_INVALID_FIELD | NVME_STATUS_DNR;
+
 	if (nvmet_is_passthru_req(req))
 		return nvmet_parse_passthru_admin_cmd(req);
 
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 3a92e3a81b46..43c9888eea90 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1122,12 +1122,15 @@ bool nvmet_req_init(struct nvmet_req *req, struct nvmet_cq *cq,
 	/*
 	 * For fabrics, PSDT field shall describe metadata pointer (MPTR) that
 	 * contains an address of a single contiguous physical buffer that is
-	 * byte aligned.
+	 * byte aligned. For PCI controllers, this is optional so not enforced.
 	 */
 	if (unlikely((flags & NVME_CMD_SGL_ALL) != NVME_CMD_SGL_METABUF)) {
-		req->error_loc = offsetof(struct nvme_common_command, flags);
-		status = NVME_SC_INVALID_FIELD | NVME_STATUS_DNR;
-		goto fail;
+		if (!req->sq->ctrl || !nvmet_is_pci_ctrl(req->sq->ctrl)) {
+			req->error_loc =
+				offsetof(struct nvme_common_command, flags);
+			status = NVME_SC_INVALID_FIELD | NVME_STATUS_DNR;
+			goto fail;
+		}
 	}
 
 	if (unlikely(!req->sq->ctrl))
@@ -1182,8 +1185,14 @@ EXPORT_SYMBOL_GPL(nvmet_req_transfer_len);
 bool nvmet_check_transfer_len(struct nvmet_req *req, size_t len)
 {
 	if (unlikely(len != req->transfer_len)) {
+		u16 status;
+
 		req->error_loc = offsetof(struct nvme_common_command, dptr);
-		nvmet_req_complete(req, NVME_SC_SGL_INVALID_DATA | NVME_STATUS_DNR);
+		if (req->cmd->common.flags & NVME_CMD_SGL_ALL)
+			status = NVME_SC_SGL_INVALID_DATA;
+		else
+			status = NVME_SC_INVALID_FIELD;
+		nvmet_req_complete(req, status | NVME_STATUS_DNR);
 		return false;
 	}
 
@@ -1194,8 +1203,14 @@ EXPORT_SYMBOL_GPL(nvmet_check_transfer_len);
 bool nvmet_check_data_len_lte(struct nvmet_req *req, size_t data_len)
 {
 	if (unlikely(data_len > req->transfer_len)) {
+		u16 status;
+
 		req->error_loc = offsetof(struct nvme_common_command, dptr);
-		nvmet_req_complete(req, NVME_SC_SGL_INVALID_DATA | NVME_STATUS_DNR);
+		if (req->cmd->common.flags & NVME_CMD_SGL_ALL)
+			status = NVME_SC_SGL_INVALID_DATA;
+		else
+			status = NVME_SC_INVALID_FIELD;
+		nvmet_req_complete(req, status | NVME_STATUS_DNR);
 		return false;
 	}
 
-- 
2.47.1