io_uring: reuse io_alloc_req()

Don't duplicate io_alloc_req() in io_req_caches_free() but reuse the
helper.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6005fc88274864a49fc3096c22d8bdd605cf8576.1665891182.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/io_uring.c

@@ -2560,18 +2560,14 @@ static int io_eventfd_unregister(struct io_ring_ctx *ctx)
 
 static void io_req_caches_free(struct io_ring_ctx *ctx)
 {
-	struct io_submit_state *state = &ctx->submit_state;
 	int nr = 0;
 
 	mutex_lock(&ctx->uring_lock);
-	io_flush_cached_locked_reqs(ctx, state);
+	io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
 
 	while (!io_req_cache_empty(ctx)) {
-		struct io_wq_work_node *node;
-		struct io_kiocb *req;
+		struct io_kiocb *req = io_alloc_req(ctx);
 
-		node = wq_stack_extract(&state->free_list);
-		req = container_of(node, struct io_kiocb, comp_list);
 		kmem_cache_free(req_cachep, req);
 		nr++;
 	}