io_uring: split io_req_complete_post() and add a helper

Split io_req_complete_post(), this is a prep for the next patch.
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211207093951.247840-5-haoxu@linux.alibaba.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -1891,12 +1891,11 @@ static noinline bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data,
 	return __io_fill_cqe(ctx, user_data, res, cflags);
 }
 
-static void io_req_complete_post(struct io_kiocb *req, s32 res,
-				 u32 cflags)
+static void __io_req_complete_post(struct io_kiocb *req, s32 res,
+				   u32 cflags)
 {
 	struct io_ring_ctx *ctx = req->ctx;
 
-	spin_lock(&ctx->completion_lock);
 	if (!(req->flags & REQ_F_CQE_SKIP))
 		__io_fill_cqe(ctx, req->user_data, res, cflags);
 	/*
@@ -1918,6 +1917,15 @@ static void io_req_complete_post(struct io_kiocb *req, s32 res,
 		wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
 		ctx->locked_free_nr++;
 	}
+}
+
+static void io_req_complete_post(struct io_kiocb *req, s32 res,
+				 u32 cflags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+
+	spin_lock(&ctx->completion_lock);
+	__io_req_complete_post(req, res, cflags);
 	io_commit_cqring(ctx);
 	spin_unlock(&ctx->completion_lock);
 	io_cqring_ev_posted(ctx);