From ae34817bd93e373a03203a4c6892735c430a14e1 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 23 Jul 2020 20:25:20 +0300 Subject: io_uring: don't do opcode prep twice Calling into opcode prep handlers may be dangerous, as they re-read SQE but might not re-initialise requests completely. If io_req_defer() passed fast checks and is done with preparations, punt it async. As all other cases are covered with nulling @sqe, this guarantees that io_[opcode]_prep() are visited only once per request. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index 6f3f18a99f4f..38e4c3902963 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5447,7 +5447,8 @@ static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe) if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) { spin_unlock_irq(&ctx->completion_lock); kfree(de); - return 0; + io_queue_async_work(req); + return -EIOCBQUEUED; } trace_io_uring_defer(ctx, req, req->user_data); -- cgit v1.2.3