BUILD_BUG_ON(sizeof(struct nvme_nvm_erase_blk) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_nvm_id_group) != 960);
        BUILD_BUG_ON(sizeof(struct nvme_nvm_addr_format) != 16);
-       BUILD_BUG_ON(sizeof(struct nvme_nvm_id) != 4096);
+       BUILD_BUG_ON(sizeof(struct nvme_nvm_id) != NVME_IDENTIFY_DATA_SIZE);
        BUILD_BUG_ON(sizeof(struct nvme_nvm_bb_tbl) != 64);
 }
 
 
        BUILD_BUG_ON(sizeof(struct nvme_format_cmd) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_abort_cmd) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_command) != 64);
-       BUILD_BUG_ON(sizeof(struct nvme_id_ctrl) != 4096);
-       BUILD_BUG_ON(sizeof(struct nvme_id_ns) != 4096);
+       BUILD_BUG_ON(sizeof(struct nvme_id_ctrl) != NVME_IDENTIFY_DATA_SIZE);
+       BUILD_BUG_ON(sizeof(struct nvme_id_ns) != NVME_IDENTIFY_DATA_SIZE);
        BUILD_BUG_ON(sizeof(struct nvme_lba_range_type) != 64);
        BUILD_BUG_ON(sizeof(struct nvme_smart_log) != 512);
        BUILD_BUG_ON(sizeof(struct nvme_dbbuf) != 64);
 
 
 static void nvmet_execute_identify_nslist(struct nvmet_req *req)
 {
-       static const int buf_size = 4096;
+       static const int buf_size = NVME_IDENTIFY_DATA_SIZE;
        struct nvmet_ctrl *ctrl = req->sq->ctrl;
        struct nvmet_ns *ns;
        u32 min_nsid = le32_to_cpu(req->cmd->identify.nsid);
                }
                break;
        case nvme_admin_identify:
-               req->data_len = 4096;
+               req->data_len = NVME_IDENTIFY_DATA_SIZE;
                switch (cmd->identify.cns) {
                case NVME_ID_CNS_NS:
                        req->execute = nvmet_execute_identify_ns;
 
                return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
                }
        case nvme_admin_identify:
-               req->data_len = 4096;
+               req->data_len = NVME_IDENTIFY_DATA_SIZE;
                switch (cmd->identify.cns) {
                case NVME_ID_CNS_CTRL:
                        req->execute =
 
        __u32                   rsvd11[5];
 };
 
+#define NVME_IDENTIFY_DATA_SIZE 4096
+
 struct nvme_features {
        __u8                    opcode;
        __u8                    flags;