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[1/3] nvme: unlink head after removing last namespace

Message ID 20210314040705.1357858-2-anton@lightbitslabs.com
State New
Headers show
Series [1/3] nvme: unlink head after removing last namespace | expand

Commit Message

Anton Eidelman March 14, 2021, 4:07 a.m. UTC 
From: Keith Busch <kbusch@kernel.org>

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>
---
 drivers/nvme/host/core.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
diff mbox series

Patch

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 */