[RFC v2 19/19] io_uring: optimise task referencing by notifiers

From: Pavel Begunkov
Date: Tue Dec 21 2021 - 10:36:56 EST


Use io_put_task()/etc. infra holding task references for notifiers, so
we can get rid of atomics there.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
fs/io_uring.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ee496b463462..0eadf4ee5402 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2008,7 +2008,7 @@ static void io_uring_tx_zerocopy_callback(struct sk_buff *skb,
if (unlikely(!notifier->task))
goto fallback;

- put_task_struct(notifier->task);
+ io_put_task(notifier->task, 1);
notifier->task = NULL;

if (!in_interrupt()) {
@@ -2034,7 +2034,8 @@ static inline void __io_tx_kill_notification(struct io_tx_ctx *tx_ctx)

static inline void io_tx_kill_notification(struct io_tx_ctx *tx_ctx)
{
- tx_ctx->notifier->task = get_task_struct(current);
+ tx_ctx->notifier->task = current;
+ io_get_task_refs(1);
__io_tx_kill_notification(tx_ctx);
}

--
2.34.1