bfq: update internal depth state when queue depth changes
A previous commit moved the shallow depth and BFQ depth map calculations
to be done at init time, moving it outside of the hotter IO path. This
potentially causes hangs if the users changes the depth of the scheduler
map, by writing to the 'nr_requests' sysfs file for that device.
Add a blk-mq-sched hook that allows blk-mq to inform the scheduler if
the depth changes, so that the scheduler can update its internal state.
Tested-by: Kai Krakow <kai@kaishome.de>
Reported-by: Paolo Valente <paolo.valente@linaro.org>
Fixes: f0635b8a416e ("bfq: calculate shallow depths at init time")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9516304..fc60ed7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3135,6 +3135,8 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
}
if (ret)
break;
+ if (q->elevator && q->elevator->type->ops.depth_updated)
+ q->elevator->type->ops.depth_updated(hctx);
}
if (!ret)