[PATCH v2 7/8] io_uring: refactor __io_cq_unlock_post_flush()

From: Pavel Begunkov
Date: Thu Apr 06 2023 - 09:21:23 EST


Separate ->task_complete path in __io_cq_unlock_post_flush().

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
io_uring/io_uring.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 8a327a81beaf..0ea50c46f27f 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -627,21 +627,23 @@ static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
io_cqring_wake(ctx);
}

-static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx)
+static void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx)
__releases(ctx->completion_lock)
{
io_commit_cqring(ctx);
- __io_cq_unlock(ctx);
- io_commit_cqring_flush(ctx);

- /*
- * As ->task_complete implies that the ring is single tasked, cq_wait
- * may only be waited on by the current in io_cqring_wait(), but since
- * it will re-check the wakeup conditions once we return we can safely
- * skip waking it up.
- */
- if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
+ if (ctx->task_complete) {
+ /*
+ * ->task_complete implies that only current might be waiting
+ * for CQEs, and obviously, we currently don't. No one is
+ * waiting, wakeups are futile, skip them.
+ */
+ io_commit_cqring_flush(ctx);
+ } else {
+ __io_cq_unlock(ctx);
+ io_commit_cqring_flush(ctx);
io_cqring_wake(ctx);
+ }
}

void io_cq_unlock_post(struct io_ring_ctx *ctx)
--
2.40.0