io-wq: simplify code in __io_worker_busy()

Leverage XOR to simplify the code in __io_worker_busy.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/1617678525-3129-1-git-send-email-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 5551272..b1c093d 100644 (file)
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -329,6 +329,8 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
 {
        bool worker_bound, work_bound;
 
+       BUILD_BUG_ON((IO_WQ_ACCT_UNBOUND ^ IO_WQ_ACCT_BOUND) != 1);
+
        if (worker->flags & IO_WORKER_F_FREE) {
                worker->flags &= ~IO_WORKER_F_FREE;
                hlist_nulls_del_init_rcu(&worker->nulls_node);
@@ -341,16 +343,11 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
        worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
        work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
        if (worker_bound != work_bound) {
+               int index = work_bound ? IO_WQ_ACCT_UNBOUND : IO_WQ_ACCT_BOUND;
                io_wqe_dec_running(worker);
-               if (work_bound) {
-                       worker->flags |= IO_WORKER_F_BOUND;
-                       wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
-                       wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
-               } else {
-                       worker->flags &= ~IO_WORKER_F_BOUND;
-                       wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
-                       wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
-               }
+               worker->flags ^= IO_WORKER_F_BOUND;
+               wqe->acct[index].nr_workers--;
+               wqe->acct[index ^ 1].nr_workers++;
                io_wqe_inc_running(worker);
         }
 }