On 3/22/19 9:04 AM, Peter Zijlstra wrote: > On Fri, Mar 22, 2019 at 04:01:16PM +0100, Peter Zijlstra wrote: >> On Fri, Mar 22, 2019 at 10:48:17PM +0800, Yufen Yu wrote: >>> @@ -2710,7 +2710,7 @@ static struct blk_mq_hw_ctx >>> *blk_mq_alloc_and_init_hctx( >>> return NULL; >>> } >>> >>> - atomic_set(&hctx->nr_active, 0); >>> + refcount_set(&hctx->nr_active, 0); >>> hctx->numa_node = node; >>> hctx->queue_num = hctx_idx; >>> >> >> That looks bogus, refcount_t cannot inc-from-zero. > > I also don't see a single dec_and_test in that patch, which leads me to > believe nr_active is not in fact a refcount.
It isn't a refcount at all, it's just a count of how many queues are active in a shared tag map scenario. -- Jens Axboe
