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>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index d2d8e60..d7de064 100644 (file)
--- 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;
                }