nvme: validate cntlid during controller initialisation

The CNTLID value is required to be unique, and we do rely on this
for correct operation. So reject any controller for which a non-unique
CNTLID has been detected.

Based on a patch from Hannes Reinecke.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>

1 files changed, 24 insertions, 17 deletions

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index d2d8e6088c46..d7de0642c832 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2341,20 +2341,35 @@ static const struct attribute_group *nvme_subsys_attrs_groups[] = {
         NULL,
 };
 
-static int nvme_active_ctrls(struct nvme_subsystem *subsys)
+static bool nvme_validate_cntlid(struct nvme_subsystem *subsys,
+                struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 {
-        int count = 0;
-        struct nvme_ctrl *ctrl;
+        struct nvme_ctrl *tmp;
 
         lockdep_assert_held(&nvme_subsystems_lock);
 
-        list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
-                if (ctrl->state != NVME_CTRL_DELETING &&
-                    ctrl->state != NVME_CTRL_DEAD)
-                        count++;
+        list_for_each_entry(tmp, &subsys->ctrls, subsys_entry) {
+                if (ctrl->state == NVME_CTRL_DELETING ||
+                    ctrl->state == NVME_CTRL_DEAD)
+                        continue;
+
+                if (tmp->cntlid == ctrl->cntlid) {
+                        dev_err(ctrl->device,
+                                "Duplicate cntlid %u with %s, rejecting\n",
+                                ctrl->cntlid, dev_name(tmp->device));
+                        return false;
+                }
+
+                if ((id->cmic & (1 << 1)) ||
+                    (ctrl->opts && ctrl->opts->discovery_nqn))
+                        continue;
+
+                dev_err(ctrl->device,
+                        "Subsystem does not support multiple controllers\n");
+                return false;
         }
 
-        return count;
+        return true;
 }
 
 static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
@@ -2397,15 +2412,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
                 __nvme_release_subsystem(subsys);
                 subsys = found;
 
-                /*
-                 * Verify that the subsystem actually supports multiple
-                 * controllers, else bail out.
-                 */
-                if (!(ctrl->opts && ctrl->opts->discovery_nqn) &&
-                    nvme_active_ctrls(found) && !(id->cmic & (1 << 1))) {
-                        dev_err(ctrl->device,
-                                "ignoring ctrl due to duplicate subnqn (%s).\n",
-                                subsys->subnqn);
+                if (!nvme_validate_cntlid(subsys, ctrl, id)) {
                         ret = -EINVAL;
                         goto out_put_subsystem;
                 }