io-wq: update hash bits

Linked requests are hashed, remove a comment stating otherwise. Also
move hash bits to emphasise that we don't carry it through loop
iteration and set it every time.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

fs/io-wq.c

@@ -490,7 +490,6 @@ static void io_worker_handle_work(struct io_worker *worker)
 
 	do {
 		struct io_wq_work *work;
-		unsigned int hash;
 get_next:
 		/*
 		 * If we got some work, mark us as busy. If we didn't, but
@@ -513,6 +512,7 @@ static void io_worker_handle_work(struct io_worker *worker)
 		/* handle a whole dependent link */
 		do {
 			struct io_wq_work *old_work, *next_hashed, *linked;
+			unsigned int hash = io_get_work_hash(work);
 
 			next_hashed = wq_next_work(work);
 			io_impersonate_work(worker, work);
@@ -523,7 +523,6 @@ static void io_worker_handle_work(struct io_worker *worker)
 			if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
 				work->flags |= IO_WQ_WORK_CANCEL;
 
-			hash = io_get_work_hash(work);
 			old_work = work;
 			linked = wq->do_work(work);
 
@@ -542,8 +541,6 @@ static void io_worker_handle_work(struct io_worker *worker)
 				spin_lock_irq(&wqe->lock);
 				wqe->hash_map &= ~BIT_ULL(hash);
 				wqe->flags &= ~IO_WQE_FLAG_STALLED;
-				/* dependent work is not hashed */
-				hash = -1U;
 				/* skip unnecessary unlock-lock wqe->lock */
 				if (!work)
 					goto get_next;