io_uring: add 'io_comp_state' to struct io_submit_state

No functional changes in this patch, just in preparation for passing back
pending completions to the caller and completing them in a batched
fashion.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -678,6 +678,12 @@ struct io_kiocb {
 
 #define IO_IOPOLL_BATCH			8
 
+struct io_comp_state {
+	unsigned int		nr;
+	struct list_head	list;
+	struct io_ring_ctx	*ctx;
+};
+
 struct io_submit_state {
 	struct blk_plug		plug;
 
@@ -687,6 +693,11 @@ struct io_submit_state {
 	void			*reqs[IO_IOPOLL_BATCH];
 	unsigned int		free_reqs;
 
+	/*
+	 * Batch completion logic
+	 */
+	struct io_comp_state	comp;
+
 	/*
 	 * File reference cache
 	 */
@@ -6006,12 +6017,15 @@ static void io_submit_state_end(struct io_submit_state *state)
  * Start submission side cache.
  */
 static void io_submit_state_start(struct io_submit_state *state,
-				  unsigned int max_ios)
+				  struct io_ring_ctx *ctx, unsigned int max_ios)
 {
 	blk_start_plug(&state->plug);
 #ifdef CONFIG_BLOCK
 	state->plug.nowait = true;
 #endif
+	state->comp.nr = 0;
+	INIT_LIST_HEAD(&state->comp.list);
+	state->comp.ctx = ctx;
 	state->free_reqs = 0;
 	state->file = NULL;
 	state->ios_left = max_ios;
@@ -6146,7 +6160,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
 	if (!percpu_ref_tryget_many(&ctx->refs, nr))
 		return -EAGAIN;
 
-	io_submit_state_start(&state, nr);
+	io_submit_state_start(&state, ctx, nr);
 
 	ctx->ring_fd = ring_fd;
 	ctx->ring_file = ring_file;