From patchwork Thu Mar 9 16:54:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13167989 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D33BC64EC4 for ; Thu, 9 Mar 2023 17:00:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229823AbjCIRAZ (ORCPT ); Thu, 9 Mar 2023 12:00:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229940AbjCIRAB (ORCPT ); Thu, 9 Mar 2023 12:00:01 -0500 Received: from mail-pl1-x634.google.com (mail-pl1-x634.google.com [IPv6:2607:f8b0:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B12980909 for ; Thu, 9 Mar 2023 08:54:14 -0800 (PST) Received: by mail-pl1-x634.google.com with SMTP id u5so2641797plq.7 for ; Thu, 09 Mar 2023 08:54:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1678380853; h=content-transfer-encoding:cc:subject:from:to:content-language :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=vqc9oMrgkQUibO1kTeMAOuc92j7JV/u9PliAiT119Ec=; b=4TlBfKRzAU8/kIvVZIv8MRxP9zd6OG5SJi42bOkpvWhFVhoz5+oy0btb8ZtsPDfymd D97bryZ518s1x1lDosVRS8PbKymXtyz5B21zCf1O7jclaAs3qQLMY60D5hZWPTntnKhD kr6IEfxnzVHguk4d9GZCGCa7CTHowV7tjjBXU0aG/cFbcbop59/QKUGtYpcUS1g8TmsP 4Oi9gqDmUgdj1DyRB269nCzFA5mSAI7xYvO8qBpSD+VLMmogjvD5Ti9ITwN+tV1yksgL y6sY8c48nrdRvCxmGWs4X0F+4kp7YkgBQlBAFG5+yv8oL9/ThdI8pHVCWJTAESNIrX7o ixHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678380853; h=content-transfer-encoding:cc:subject:from:to:content-language :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=vqc9oMrgkQUibO1kTeMAOuc92j7JV/u9PliAiT119Ec=; b=bw7yZMlTDIBRM48XH20nNmE5QwJdIQYn36WsmBleBRiCxD4/eW5nXLz+LqQlp+4f55 Y26DAHy81nu/ytOfXIZXgMpbzLCnqtT8zpcJB3NlsCiBHuk78nbpR+QNxY7fj6/Z+U8l slAzyppysWbO2jmPLDF9ey8x/7qT6iTeZMKByxfu0XU7OUHeyCxkexQACdGgm52cdjCH 4fSy37+IO30Bi/SZWXG7/+MqZcm42hnk1GwiNJkD2NRPvJpCB86brCHiDB8z6615RmR8 aC2Ylz8Y6bcrfyLy3R5EFtSPfuaoQgwomElSMPWE7fKzDR6EM6XoNM6RF9CzWbkHFueA G5Ag== X-Gm-Message-State: AO0yUKXhflHwLlubhQJtX9s/v0m6SdQPxcl2chrzzQAV938WHqZCUDOh ocV9itSBiXlxwS6ENfBs9LXEmRcD8iJvTVMhzxY1Vw== X-Google-Smtp-Source: AK7set+GKn8OXAClmQWPU/r9Hjk8Win68Kj2wr7yZ8b+aGMyVvZZIHhHAjDQOErq5W8wS7Wf9l9bQA== X-Received: by 2002:a17:903:84e:b0:19d:1e21:7f59 with SMTP id ks14-20020a170903084e00b0019d1e217f59mr3722383plb.0.1678380853259; Thu, 09 Mar 2023 08:54:13 -0800 (PST) Received: from [172.20.4.229] ([50.233.106.125]) by smtp.gmail.com with ESMTPSA id kv3-20020a17090328c300b0019c922911a2sm11886371plb.40.2023.03.09.08.54.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Mar 2023 08:54:12 -0800 (PST) Message-ID: Date: Thu, 9 Mar 2023 09:54:12 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Content-Language: en-US To: io-uring From: Jens Axboe Subject: =?utf-8?q?=5BPATCH=5D_io=5Furing=3A_silence_variable_=E2=80=98prev?= =?utf-8?q?=E2=80=99_set_but_not_used_warning?= Cc: Vincenzo Palazzo Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org If io_uring.o is built with W=1, it triggers a warning: io_uring/io_uring.c: In function ?__io_submit_flush_completions?: io_uring/io_uring.c:1502:40: warning: variable ?prev? set but not used [-Wunused-but-set-variable] 1502 | struct io_wq_work_node *node, *prev; | ^~~~ which is due to the wq_list_for_each() iterator always keeping a 'prev' variable. Most users need this to remove an entry from a list, for example, but __io_submit_flush_completions() never does that. Add a basic helper that doesn't track prev instead, and use that in that function. Reported-by: Vincenzo Palazzo Signed-off-by: Jens Axboe diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index fd1cc35a1c00..722624b6d0dc 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1499,14 +1499,14 @@ void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node) static void __io_submit_flush_completions(struct io_ring_ctx *ctx) __must_hold(&ctx->uring_lock) { - struct io_wq_work_node *node, *prev; struct io_submit_state *state = &ctx->submit_state; + struct io_wq_work_node *node; __io_cq_lock(ctx); /* must come first to preserve CQE ordering in failure cases */ if (state->cqes_count) __io_flush_post_cqes(ctx); - wq_list_for_each(node, prev, &state->compl_reqs) { + __wq_list_for_each(node, &state->compl_reqs) { struct io_kiocb *req = container_of(node, struct io_kiocb, comp_list); diff --git a/io_uring/slist.h b/io_uring/slist.h index 7c198a40d5f1..0eb194817242 100644 --- a/io_uring/slist.h +++ b/io_uring/slist.h @@ -3,6 +3,9 @@ #include +#define __wq_list_for_each(pos, head) \ + for (pos = (head)->first; pos; pos = (pos)->next) + #define wq_list_for_each(pos, prv, head) \ for (pos = (head)->first, prv = NULL; pos; prv = pos, pos = (pos)->next) @@ -113,4 +116,4 @@ static inline struct io_wq_work *wq_next_work(struct io_wq_work *work) return container_of(work->list.next, struct io_wq_work, list); } -#endif // INTERNAL_IO_SLIST_H \ No newline at end of file +#endif // INTERNAL_IO_SLIST_H