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nvme: unlink head after removing last namespace

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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>
This commit is contained in:
Keith Busch 2020-04-09 09:08:59 -07:00 committed by Jens Axboe
parent aec459b484
commit d567572906
1 changed files with 5 additions and 2 deletions
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7
drivers/nvme/host/core.c
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@ -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 */