From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7AEA9C433DF for ; Wed, 20 May 2020 04:41:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 652DB2075F for ; Wed, 20 May 2020 04:41:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726634AbgETEle (ORCPT ); Wed, 20 May 2020 00:41:34 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:50409 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726309AbgETEld (ORCPT ); Wed, 20 May 2020 00:41:33 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R921e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04357;MF=xiaoguang.wang@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0Tz4XTU1_1589949681; Received: from localhost(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0Tz4XTU1_1589949681) by smtp.aliyun-inc.com(127.0.0.1); Wed, 20 May 2020 12:41:30 +0800 From: Xiaoguang Wang To: io-uring@vger.kernel.org Cc: axboe@kernel.dk, joseph.qi@linux.alibaba.com, Xiaoguang Wang Subject: [PATCH] io_uring: reset -EBUSY error when io sq thread is waken up Date: Wed, 20 May 2020 12:40:59 +0800 Message-Id: <20200520044059.2308-1-xiaoguang.wang@linux.alibaba.com> X-Mailer: git-send-email 2.17.2 Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org In io_sq_thread(), currently if we get an -EBUSY error, we will won't clear it again, which will result in io_sq_thread() will never have a chance to submit sqes again. Below test program test.c can reveal this bug: int main(int argc, char *argv[]) { struct io_uring ring; int i, fd, ret; struct io_uring_sqe *sqe; struct io_uring_cqe *cqe; struct iovec *iovecs; void *buf; struct io_uring_params p; if (argc < 2) { printf("%s: file\n", argv[0]); return 1; } memset(&p, 0, sizeof(p)); p.flags = IORING_SETUP_SQPOLL; ret = io_uring_queue_init_params(4, &ring, &p); if (ret < 0) { fprintf(stderr, "queue_init: %s\n", strerror(-ret)); return 1; } fd = open(argv[1], O_RDONLY | O_DIRECT); if (fd < 0) { perror("open"); return 1; } iovecs = calloc(10, sizeof(struct iovec)); for (i = 0; i < 10; i++) { if (posix_memalign(&buf, 4096, 4096)) return 1; iovecs[i].iov_base = buf; iovecs[i].iov_len = 4096; } ret = io_uring_register_files(&ring, &fd, 1); if (ret < 0) { fprintf(stderr, "%s: register %d\n", __FUNCTION__, ret); return ret; } for (i = 0; i < 10; i++) { sqe = io_uring_get_sqe(&ring); if (!sqe) break; io_uring_prep_readv(sqe, 0, &iovecs[i], 1, 0); sqe->flags |= IOSQE_FIXED_FILE; ret = io_uring_submit(&ring); sleep(1); printf("submit %d\n", i); } for (i = 0; i < 10; i++) { io_uring_wait_cqe(&ring, &cqe); printf("receive: %d\n", i); if (cqe->res != 4096) { fprintf(stderr, "ret=%d, wanted 4096\n", cqe->res); ret = 1; } io_uring_cqe_seen(&ring, cqe); } close(fd); io_uring_queue_exit(&ring); return 0; } sudo ./test testfile above command will hang on the tenth request, to fix this bug, when io sq_thread is waken up, we reset the variable 'ret' to be zero. Signed-off-by: Xiaoguang Wang --- fs/io_uring.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6e51140a5722..747de5cdf38a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6045,6 +6045,8 @@ static int io_sq_thread(void *data) finish_wait(&ctx->sqo_wait, &wait); ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP; + if (ret == -EBUSY) + ret = 0; continue; } finish_wait(&ctx->sqo_wait, &wait); -- 2.17.2