[PATCH v2] nvme: verify MNAN value if ANA is enabled

[Daniel Wagner <dwagner@suse.de>]

The controller is required to have a non-zero MNAN value if it supports
ANA:

   If the controller supports Asymmetric Namespace Access Reporting, then
   this field shall be set to a non-zero value that is less than or equal
   to the NN value.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
---

v2: - moved the check to nvme_mpath_init_identify
    - added reviewed tags

 drivers/nvme/host/multipath.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index a501917d4c6e..23573fe3fc7d 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -813,6 +813,13 @@ int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 	    !(ctrl->subsys->cmic & NVME_CTRL_CMIC_ANA))
 		return 0;
 
+	if (!ctrl->max_namespaces ||
+	    ctrl->max_namespaces > le32_to_cpu(id->nn)) {
+		dev_err(ctrl->device,
+			"Invalid MNAN value %u\n", ctrl->max_namespaces);
+		return -EINVAL;
+	}
+
 	ctrl->anacap = id->anacap;
 	ctrl->anatt = id->anatt;
 	ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
-- 
2.29.2