From 42de82a8b544fa55670feef7d6f85085fba48fc0 Mon Sep 17 00:00:00 2001
From: Martin Wilck <mwilck@suse.com>
Date: Fri, 14 Jul 2017 00:25:31 +0200
Subject: [PATCH] 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 <mwilck@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
[hch: fixed for the move of the serial field, updated description]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 drivers/nvme/target/admin-cmd.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index f7ba006d6a656..2d7a98ab53fbf 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -168,11 +168,21 @@ static void nvmet_execute_get_log_page(struct nvmet_req *req)
 	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));
-- 
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