io_uring: lockless task list

With networking use cases we see contention on the spinlock used to
protect the task_list when multiple threads try and add completions at once.
Instead we can use a lockless list, and assume that the first caller to
add to the list is responsible for kicking off task work.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220622134028.2013417-4-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 5987f8acca38..918165a20053 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -428,7 +428,7 @@ typedef void (*io_req_tw_func_t)(struct io_kiocb *req, bool *locked);
 
 struct io_task_work {
 	union {
-		struct io_wq_work_node	node;
+		struct llist_node	node;
 		struct llist_node	fallback_node;
 	};
 	io_req_tw_func_t		func;