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Commit eb565f05 authored by Keith Busch's avatar Keith Busch Committed by Greg Kroah-Hartman
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nvme: unlink head after removing last namespace 



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: default avatarKeith Busch <kbusch@kernel.org>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4535fb9e

drivers/nvme/host/core.c

+5 −2
Original line number Diff line number Diff line
@@ -455,7 +455,6 @@ 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);
@@ -3374,7 +3373,6 @@ 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;

	}
@@ -3629,6 +3627,8 @@ static int 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:
@@ -3651,7 +3651,10 @@ 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 */