nvmet: Introduce nvmet_req_transfer_len()

Add the new function nvmet_req_transfer_len() to parse a request command
to extract the transfer length of the command. This function
implementation relies on multiple helper functions for parsing I/O
commands (nvmet_io_cmd_transfer_len()), admin commands
(nvmet_admin_cmd_data_len()) and fabrics connect commands
(nvmet_connect_cmd_data_len).

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 78478a4a2e4d..6f7e5b0c91c7 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -1296,6 +1296,27 @@ out:
 	nvmet_req_complete(req, status);
 }
 
+u32 nvmet_admin_cmd_data_len(struct nvmet_req *req)
+{
+	struct nvme_command *cmd = req->cmd;
+
+	if (nvme_is_fabrics(cmd))
+		return nvmet_fabrics_admin_cmd_data_len(req);
+	if (nvmet_is_disc_subsys(nvmet_req_subsys(req)))
+		return nvmet_discovery_cmd_data_len(req);
+
+	switch (cmd->common.opcode) {
+	case nvme_admin_get_log_page:
+		return nvmet_get_log_page_len(cmd);
+	case nvme_admin_identify:
+		return NVME_IDENTIFY_DATA_SIZE;
+	case nvme_admin_get_features:
+		return nvmet_feat_data_len(req, le32_to_cpu(cmd->common.cdw10));
+	default:
+		return 0;
+	}
+}
+
 u16 nvmet_parse_admin_cmd(struct nvmet_req *req)
 {
 	struct nvme_command *cmd = req->cmd;