From d567572906d986dedb78b37f111c44eba033f3ef Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 9 Apr 2020 09:08:59 -0700 Subject: [PATCH] nvme: unlink head after removing last namespace The driver had been unlinking the namespace head from the subsystem's list only after the last reference was released, and outside of the list's subsys->lock protection. There is no reason to track an empty head, so unlink the entry from the subsystem's list when the last namespace using that head is removed and with the mutex lock protecting the list update. The next namespace to attach reusing the previous NSID will allocate a new head rather than find the old head with mismatched identifiers. Signed-off-by: Keith Busch Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/nvme/host/core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index d0f65322156c..15b9e60be204 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -433,7 +433,6 @@ static void nvme_free_ns_head(struct kref *ref) nvme_mpath_remove_disk(head); ida_simple_remove(&head->subsys->ns_ida, head->instance); - list_del_init(&head->entry); cleanup_srcu_struct(&head->srcu); nvme_put_subsystem(head->subsys); kfree(head); @@ -3414,7 +3413,6 @@ static int __nvme_check_ids(struct nvme_subsystem *subsys, list_for_each_entry(h, &subsys->nsheads, entry) { if (nvme_ns_ids_valid(&new->ids) && - !list_empty(&h->list) && nvme_ns_ids_equal(&new->ids, &h->ids)) return -EINVAL; } @@ -3660,6 +3658,8 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid) out_unlink_ns: mutex_lock(&ctrl->subsys->lock); list_del_rcu(&ns->siblings); + if (list_empty(&ns->head->list)) + list_del_init(&ns->head->entry); mutex_unlock(&ctrl->subsys->lock); nvme_put_ns_head(ns->head); out_free_id: @@ -3679,7 +3679,10 @@ static void nvme_ns_remove(struct nvme_ns *ns) mutex_lock(&ns->ctrl->subsys->lock); list_del_rcu(&ns->siblings); + if (list_empty(&ns->head->list)) + list_del_init(&ns->head->entry); mutex_unlock(&ns->ctrl->subsys->lock); + synchronize_rcu(); /* guarantee not available in head->list */ nvme_mpath_clear_current_path(ns); synchronize_srcu(&ns->head->srcu); /* wait for concurrent submissions */