nvmet: don't report 0-bytes in serial number

The NVME standard mandates that the SN, MN, and FR fields of the Identify
Controller Data Structure be "ASCII strings".  That means that they may
not contain 0-bytes, not even string terminators.

Signed-off-by: Martin Wilck <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
[hch: fixed for the move of the serial field, updated description]
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

1 files changed, 14 insertions, 2 deletions

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index f7ba006d6a65..2d7a98ab53fb 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -168,11 +168,21 @@ out:
 	nvmet_req_complete(req, status);
 }
 
+static void copy_and_pad(char *dst, int dst_len, const char *src, int src_len)
+{
+	int len = min(src_len, dst_len);
+
+	memcpy(dst, src, len);
+	if (dst_len > len)
+		memset(dst + len, ' ', dst_len - len);
+}
+
 static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 {
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	struct nvme_id_ctrl *id;
 	u16 status = 0;
+	const char model[] = "Linux";
 
 	id = kzalloc(sizeof(*id), GFP_KERNEL);
 	if (!id) {
@@ -184,8 +194,10 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 	id->vid = 0;
 	id->ssvid = 0;
 
-	memset(id->sn, ' ', sizeof(id->sn));
-	snprintf(id->sn, sizeof(id->sn), "%llx", ctrl->subsys->serial);
+	bin2hex(id->sn, &ctrl->subsys->serial,
+		min(sizeof(ctrl->subsys->serial), sizeof(id->sn) / 2));
+	copy_and_pad(id->mn, sizeof(id->mn), model, sizeof(model) - 1);
+	copy_and_pad(id->fr, sizeof(id->fr), UTS_RELEASE, strlen(UTS_RELEASE));
 
 	memset(id->mn, ' ', sizeof(id->mn));
 	strncpy((char *)id->mn, "Linux", sizeof(id->mn));