From: Christoph Hellwig <hch@lst.de>
Date: Thu, 31 May 2018 18:23:48 +0200
Subject: [PATCH] nvmet: return all zeroed buffer when we can't find an active
 namespace
References: bsc#1054245
Git-commit: f39ae4719b1c33d048aa4d3c284d82ecf252742b
Patch-mainline: v4.18-rc1

Quote from Figure 106 in NVMe 1.3a:

  The Identify Namespace data structure is returned to the host for the
  namespace specified in the Namespace Identifier (CDW1.NSID) field if it
  is an active NSID. If the specified namespace is not an active NSID,
  then the controller returns a zero filled data structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@rimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/nvme/target/admin-cmd.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 4c39eb4ac366..30073d2ca76a 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -270,8 +270,7 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 	struct nvme_id_ns *id;
 	u16 status = 0;
 
-	ns = nvmet_find_namespace(req->sq->ctrl, req->cmd->identify.nsid);
-	if (!ns) {
+	if (le32_to_cpu(req->cmd->identify.nsid) == NVME_NSID_ALL) {
 		status = NVME_SC_INVALID_NS | NVME_SC_DNR;
 		goto out;
 	}
@@ -279,9 +278,14 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 	id = kzalloc(sizeof(*id), GFP_KERNEL);
 	if (!id) {
 		status = NVME_SC_INTERNAL;
-		goto out_put_ns;
+		goto out;
 	}
 
+	/* return an all zeroed buffer if we can't find an active namespace */
+	ns = nvmet_find_namespace(req->sq->ctrl, req->cmd->identify.nsid);
+	if (!ns)
+		goto done;
+
 	/*
 	 * nuse = ncap = nsze isn't always true, but we have no way to find
 	 * that out from the underlying device.
@@ -306,11 +310,10 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 
 	id->lbaf[0].ds = ns->blksize_shift;
 
+	nvmet_put_namespace(ns);
+done:
 	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
-
 	kfree(id);
-out_put_ns:
-	nvmet_put_namespace(ns);
 out:
 	nvmet_req_complete(req, status);
 }
-- 
2.12.3