[PATCH 5.4 162/168] nvme: unlink head after removing last namespace
From: gregkh@linuxfoundation.org
Date: 2021-03-15 14:36:56
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> From: Keith Busch <kbusch@kernel.org> commit d567572906d986dedb78b37f111c44eba033f3ef upstream. 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 <kbusch@kernel.org> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/nvme/host/core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c@@ -455,7 +455,6 @@ static void nvme_free_ns_head(struct kre 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);
@@ -3374,7 +3373,6 @@ static int __nvme_check_ids(struct nvme_ 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; }
@@ -3629,6 +3627,8 @@ static int nvme_alloc_ns(struct nvme_ctr 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:
@@ -3651,7 +3651,10 @@ static void nvme_ns_remove(struct nvme_n 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 */