io_uring: prolong tctx_task_work() with flushing

io_submit_flush_completions() may enqueue linked requests for task_work
execution, so don't leave tctx_task_work() right after the tw list is
exhausted, but try to flush and then retry.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0755d4c2c36301447c63bdd4146c10477cea4249.1630539342.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9f3f8a8..3a7145a 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2102,6 +2102,9 @@ static void tctx_task_work(struct callback_head *cb)
        while (1) {
                struct io_wq_work_node *node;
 
+               if (!tctx->task_list.first && locked && ctx->submit_state.compl_nr)
+                       io_submit_flush_completions(ctx);
+
                spin_lock_irq(&tctx->task_lock);
                node = tctx->task_list.first;
                INIT_WQ_LIST(&tctx->task_list);