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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 086EFC432C0 for ; Wed, 20 Nov 2019 12:02:30 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C931722419 for ; Wed, 20 Nov 2019 12:02:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aX4p3vup" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C931722419 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56984 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iXOgm-0007iJ-Nf for qemu-devel@archiver.kernel.org; Wed, 20 Nov 2019 07:02:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:44480) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iXOU7-0000Tg-Dx for qemu-devel@nongnu.org; Wed, 20 Nov 2019 06:49:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iXOU5-000559-0R for qemu-devel@nongnu.org; Wed, 20 Nov 2019 06:49:22 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:57823 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iXOU4-0004xE-F0 for qemu-devel@nongnu.org; Wed, 20 Nov 2019 06:49:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574250556; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=c7zL4BWYa1kSA5bSg/wi1aR7CmPuK6fmUFk3vyoIfJ0=; b=aX4p3vup3ugSNg4UX9Ow1ZKtWq+Xz87fKAcPGWY0wvVhkOr81HVkAalmJct7ocfSEf7h2B 9Vu6Tlut0trYPONjN6KbMD9BKwRNm0/qK4DEku9ZeGuL3Ow80aiF00bLxenE5hml7u8xLF d/qdS0349i7XlSeM1zZEhtYJaEosRwo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-307-K8ZsKewIM7apsVCHFjqSDA-1; Wed, 20 Nov 2019 06:49:14 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5EBEC18C35B6 for ; Wed, 20 Nov 2019 11:49:13 +0000 (UTC) Received: from redhat.com (ovpn-112-57.ams2.redhat.com [10.36.112.57]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5ED6760BB2; Wed, 20 Nov 2019 11:48:58 +0000 (UTC) Date: Wed, 20 Nov 2019 11:48:56 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Stefan Hajnoczi Subject: Re: [PATCH] vhost-user-input: use free(elem) instead of g_free(elem) Message-ID: <20191120114856.GG2785116@redhat.com> References: <20191119111626.112206-1-stefanha@redhat.com> MIME-Version: 1.0 In-Reply-To: <20191119111626.112206-1-stefanha@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: K8ZsKewIM7apsVCHFjqSDA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: "Michael S. Tsirkin" , qemu-devel@nongnu.org, Gerd Hoffmann Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Nov 19, 2019 at 11:16:26AM +0000, Stefan Hajnoczi wrote: > The virtqueue element returned by vu_queue_pop() is allocated using > malloc(3) by virtqueue_alloc_element(). Use the matching free(3) > function instead of glib's g_free(). Just as an FYI, since glib 2.46 g_malloc is hardcoded to use the system allocator, so it is now guaranteed that g_malloc/malloc and g_free/free are safely interchangable. I recently got this clarified in the glib docs: https://gitlab.gnome.org/GNOME/glib/merge_requests/1099//diffs QEMU mandates 2.48 so we are now safe in that regard For readability/sanity sake I'd still suggest matching functions but it is not a functional danger any more. Even when it was a risk, that risk only arose if you called GLib's API for installing a custom allocator callback which QEMU never did, so it was always a non-issue. Where this is most helpful is in exchanging allocated data with 3rd party libraries that don't use glib. We no longer have to worry about dup'ing memory going in/out libraries not using glib's allocators. >=20 > Signed-off-by: Stefan Hajnoczi > --- > contrib/vhost-user-input/main.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) >=20 > diff --git a/contrib/vhost-user-input/main.c b/contrib/vhost-user-input/m= ain.c > index 449fd2171a..ef4b7769f2 100644 > --- a/contrib/vhost-user-input/main.c > +++ b/contrib/vhost-user-input/main.c > @@ -77,7 +77,7 @@ static void vi_input_send(VuInput *vi, struct virtio_in= put_event *event) > len =3D iov_from_buf(elem->in_sg, elem->in_num, > 0, &vi->queue[i].event, sizeof(virtio_input_e= vent)); > vu_queue_push(dev, vq, elem, len); > - g_free(elem); > + free(elem); > } > =20 > vu_queue_notify(&vi->dev.parent, vq); > @@ -153,7 +153,7 @@ static void vi_handle_sts(VuDev *dev, int qidx) > 0, &event, sizeof(event)); > vi_handle_status(vi, &event); > vu_queue_push(dev, vq, elem, len); > - g_free(elem); > + free(elem); > } > =20 > vu_queue_notify(&vi->dev.parent, vq); > --=20 > 2.23.0 >=20 >=20 Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberrange= :| |: https://libvirt.org -o- https://fstop138.berrange.com= :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange= :|