On 10/19/20 10:42 AM, Hui Su wrote: > 1.reduce the critical section in elevator_get(). > 2.reduce the critical section in elevator_get_by_features(). > 3.remove the found variable. > > the elv_list_lock is used to protect the elv_list, > and the operations of elevator_type does not need > to be protected. > > Signed-off-by: Hui Su <sh_def@xxxxxxx> > --- > block/elevator.c | 14 ++++++-------- > 1 file changed, 6 insertions(+), 8 deletions(-) > > diff --git a/block/elevator.c b/block/elevator.c > index 293c5c81397a..727902b31954 100644 > --- a/block/elevator.c > +++ b/block/elevator.c > @@ -151,11 +151,11 @@ static struct elevator_type *elevator_get(struct request_queue *q, > spin_lock(&elv_list_lock); > e = elevator_find(name, q->required_elevator_features); > } > + spin_unlock(&elv_list_lock); > > if (e && !try_module_get(e->elevator_owner)) > e = NULL; > > - spin_unlock(&elv_list_lock); > return e; > } What happens for: A B spin_unlock(&elv_list_lock); rmmod -> elv_unregister(); try_module_get(); -- Jens Axboe
