[PATCH RFC 3/3] nvmet: report ns's vwc not present

[Guixin Liu <kanie@linux.alibaba.com>]

Currently, we report that controller has vwc even though the ns may
not have vwc. Report ns's vwc not present when not buffered_io or
backdev doesn't have vwc.

Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
---
 drivers/nvme/target/admin-cmd.c | 36 +++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 081f0473cd9e..dffb84f560ad 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -685,6 +685,39 @@ static void nvmet_execute_identify_ctrl_nvm(struct nvmet_req *req)
 		   nvmet_zero_sgl(req, 0, sizeof(struct nvme_id_ctrl_nvm)));
 }
 
+static void nvmet_execute_identify_cs_indep(struct nvmet_req *req)
+{
+	struct nvme_id_ns_cs_indep *id;
+	u16 status;
+
+	status = nvmet_req_find_ns(req);
+	if (status)
+		goto out;
+
+	id = kzalloc(sizeof(*id), GFP_KERNEL);
+	if (!id) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	if ((req->ns->file && !req->ns->buffered_io) ||
+	    (req->ns->bdev && !bdev_write_cache(req->ns->bdev)))
+		id->nsfeat |= NVME_NS_VWC_NOT_PRESENT;
+
+	id->nmic |= NVME_NS_NMIC_SHARED;
+	///TODO: report reservation supported when that patch applied.
+	id->anagrpid = cpu_to_le32(req->ns->anagrpid);
+
+	if (req->ns->readonly)
+		id->nsattr |= NVME_NS_ATTR_RO;
+	id->nstat = NVME_NSTAT_NRDY;
+
+	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
+	kfree(id);
+out:
+	nvmet_req_complete(req, status);
+}
+
 static void nvmet_execute_identify(struct nvmet_req *req)
 {
 	if (!nvmet_check_transfer_len(req, NVME_IDENTIFY_DATA_SIZE))
@@ -729,6 +762,9 @@ static void nvmet_execute_identify(struct nvmet_req *req)
 			break;
 		}
 		break;
+	case NVME_ID_CNS_NS_CS_INDEP:
+		nvmet_execute_identify_cs_indep(req);
+		return;
 	}
 
 	pr_debug("unhandled identify cns %d on qid %d\n",
-- 
2.43.0