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nvmet: protect nvmet_ports_list with nvmet_config_sem

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Readers of nvmet_ports_list (e.g. nvmet_subsys_disc_changed()) hold
nvmet_config_sem and assert it via lockdep.  The writers --
nvmet_ports_make() and nvmet_port_release() -- do not take the lock;
they rely on the parent directory's VFS inode lock for serialization,
which is an implementation detail of configfs and not a guaranteed
contract.  Align the writers with the lock the readers already require.

Also move list_add() in nvmet_ports_make() to after the port is fully
initialized: the old position published the port on the global list
before INIT_LIST_HEAD(&port->subsystems), so a concurrent reader
could traverse uninitialized list heads.

flush_workqueue() in nvmet_port_release() stays outside the semaphore
to avoid a lock dependency on nvmet_wq.

Fixes: b662a07857 ("nvmet: enable Discovery Controller AENs")
Reviewed-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Qing Zhang <diasyzhang@tencent.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
This commit is contained in:
Qing Zhang 2026-10-23 19:29:28 +08:00 committed by Keith Busch
parent a563f13a54
commit cead6beb89
1 changed files with 6 additions and 2 deletions
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8
drivers/nvme/target/configfs.c
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@ -2103,7 +2103,9 @@ static void nvmet_port_release(struct config_item *item)
/* Let inflight controllers teardown complete */
flush_workqueue(nvmet_wq);
down_write(&nvmet_config_sem);
list_del(&port->global_entry);
up_write(&nvmet_config_sem);
key_put(port->keyring);
kfree(port);
@ -2164,8 +2166,6 @@ static struct config_group *nvmet_ports_make(struct config_group *group,
port->ana_state[i] = NVME_ANA_INACCESSIBLE;
}
list_add(&port->global_entry, &nvmet_ports_list);
INIT_LIST_HEAD(&port->entry);
INIT_LIST_HEAD(&port->subsystems);
INIT_LIST_HEAD(&port->referrals);
@ -2199,6 +2199,10 @@ static struct config_group *nvmet_ports_make(struct config_group *group,
configfs_add_default_group(&port->ana_default_group.group,
&port->ana_groups_group);
down_write(&nvmet_config_sem);
list_add(&port->global_entry, &nvmet_ports_list);
up_write(&nvmet_config_sem);
return &port->group;
}