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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5541CC433EF for ; Tue, 14 Jun 2022 09:26:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241115AbiFNJ0j (ORCPT ); Tue, 14 Jun 2022 05:26:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241072AbiFNJ0i (ORCPT ); Tue, 14 Jun 2022 05:26:38 -0400 Received: from mail-yb1-xb2b.google.com (mail-yb1-xb2b.google.com [IPv6:2607:f8b0:4864:20::b2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E006EBE2D for ; Tue, 14 Jun 2022 02:26:36 -0700 (PDT) Received: by mail-yb1-xb2b.google.com with SMTP id p13so14198412ybm.1 for ; Tue, 14 Jun 2022 02:26:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=V/BnXF4Po6lT1XZ2J8UaiK92xTYbPrXaIJWtM2yCsTs=; b=DmEJPrYQ5KRdr/IysRapxIrM6PLZSlQCFCpbJa66mnsMYTCh8iqWd75CUkzo8QomQ8 AdGsm/f5u2/noUYgSk7sCqDub+p3NZD8rDm6XjFL8FPXOYnZZZsrd2gjOXnsNZKEdTzn NRJlKSHnKC7wkCTLE2Nb66+t69XLGhqE4LqlYeBk6ozNqwJjyaQG70hKLcuezkp6CT4M snxQAqH4IK3Rj+w5Lh/vsaHZ3pvO2BitKp6YXcqJdU2Ey8/cnTp+ZL6dYQTSs31IOjQ8 0xMuZvhxvzYZVsWY/1ugMuiA5lLo33JV0kLwUbNI6Z2YXp0dbVfKbAYjegB9tgqDzvYQ PY/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=V/BnXF4Po6lT1XZ2J8UaiK92xTYbPrXaIJWtM2yCsTs=; b=c8XwJ/1PqpN3C2esKz3yQNm/+7daCOttb4G2/qQ667t8tkKH31TdMRVwiUR9zQVdUB KgmQdSFFur99fKLutRSbTt5GcrlWdI8C6aLk5VpaW+UDWyfgzaGsshp1zgzHsCdoQC26 tX8R/ytA73Lf7eXH0pBmZmJV7ML5f/q4fN75yrYGsY7Fb75841Bl8IDyKxNJY73a6YZI 2c7upFOPEASqwz6hPihdqUURBvm39Pw8bIu73eLtSMsaQRXbV7WfVgMCoJVaJRZhbZYw ZoO7kPXubEU8DX7px4JgNM9yFWqvdmUQoehTHsrMW/e9+vbyiTk48O8V2R4hHk9I5zNP 6mrQ== X-Gm-Message-State: AJIora/922Zkv5CbWFzkrSjkZQFId6Oe66GU7zEkhPrEACa1klnruPhy xy4Tq2CMtfX269mqLuBa4qYGIxAJXOPk0JN3RZ01XQ== X-Google-Smtp-Source: AGRyM1u3euMHtMvSA3zS5wPrpM58C3v/B1a3dw8lQ53DFIsPSQpTHB/39Y7pVNF6nJbISO77GRAPVIoO5s1To7sUX7M= X-Received: by 2002:a25:b218:0:b0:664:6da5:b5c5 with SMTP id i24-20020a25b218000000b006646da5b5c5mr4062165ybj.6.1655198796171; Tue, 14 Jun 2022 02:26:36 -0700 (PDT) MIME-Version: 1.0 References: <20220614091359.124571-1-dzm91@hust.edu.cn> In-Reply-To: <20220614091359.124571-1-dzm91@hust.edu.cn> From: Muchun Song Date: Tue, 14 Jun 2022 17:26:00 +0800 Message-ID: Subject: Re: [PATCH] fs: io_uring: remove NULL check before kfree To: Dongliang Mu Cc: Jens Axboe , Pavel Begunkov , mudongliang , io-uring@vger.kernel.org, LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Tue, Jun 14, 2022 at 5:14 PM Dongliang Mu wrote: > > From: mudongliang > > kfree can handle NULL pointer as its argument. > According to coccinelle isnullfree check, remove NULL check > before kfree operation. > > Signed-off-by: mudongliang > --- > fs/io_uring.c | 15 +++++---------- > 1 file changed, 5 insertions(+), 10 deletions(-) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index 3aab4182fd89..bec47eae2a9b 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -3159,8 +3159,7 @@ static void io_free_batch_list(struct io_ring_ctx *ctx, > if ((req->flags & REQ_F_POLLED) && req->apoll) { > struct async_poll *apoll = req->apoll; > > - if (apoll->double_poll) > - kfree(apoll->double_poll); > + kfree(apoll->double_poll); > list_add(&apoll->poll.wait.entry, > &ctx->apoll_cache); > req->flags &= ~REQ_F_POLLED; > @@ -4499,8 +4498,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags) > kiocb_done(req, ret, issue_flags); > out_free: > /* it's faster to check here then delegate to kfree */ I am feeling you are not on the right way. See the comment here. Thanks. > - if (iovec) > - kfree(iovec); > + kfree(iovec); > return 0; > } > > @@ -4602,8 +4600,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags) > } > out_free: > /* it's reportedly faster than delegating the null check to kfree() */ See here. > - if (iovec) > - kfree(iovec); > + kfree(iovec); > return ret; > } > > @@ -6227,8 +6224,7 @@ static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags) > req_set_fail(req); > } > /* fast path, check for non-NULL to avoid function call */ here. > - if (kmsg->free_iov) > - kfree(kmsg->free_iov); > + kfree(kmsg->free_iov); > req->flags &= ~REQ_F_NEED_CLEANUP; > if (ret >= 0) > ret += sr->done_io; > @@ -6481,8 +6477,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) > } > > /* fast path, check for non-NULL to avoid function call */ And here. > - if (kmsg->free_iov) > - kfree(kmsg->free_iov); > + kfree(kmsg->free_iov); > req->flags &= ~REQ_F_NEED_CLEANUP; > if (ret >= 0) > ret += sr->done_io; > -- > 2.35.1 >