nvmet: protect nvmet_ports_list with nvmet_config_sem

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: b662a078576e ("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>

0 files changed, 0 insertions, 0 deletions