From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54660) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fIskf-0005kA-IK for qemu-devel@nongnu.org; Wed, 16 May 2018 05:29:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fIske-00085W-M0 for qemu-devel@nongnu.org; Wed, 16 May 2018 05:29:41 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43034 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fIske-00085N-HX for qemu-devel@nongnu.org; Wed, 16 May 2018 05:29:40 -0400 References: <20180515134950.3755-1-muriloo@linux.ibm.com> From: David Hildenbrand Message-ID: <109f249c-eee7-5bc9-9f59-b64bca6da5aa@redhat.com> Date: Wed, 16 May 2018 11:29:38 +0200 MIME-Version: 1.0 In-Reply-To: <20180515134950.3755-1-muriloo@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] HACKING: document preference for g_new instead of g_malloc List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Murilo Opsfelder Araujo , qemu-devel@nongnu.org Cc: Eduardo Habkost , Markus Armbruster , Paolo Bonzini On 15.05.2018 15:49, Murilo Opsfelder Araujo wrote: > This patch documents the preference for g_new instead of g_malloc. The > reasons were adapted from commit b45c03f585ea9bb1af76c73e82195418c294919d. > > Discussion in QEMU's mailing list: > http://lists.nongnu.org/archive/html/qemu-devel/2018-05/msg03238.html > > Cc: qemu-devel@nongnu.org > Cc: David Hildenbrand > Cc: Eduardo Habkost > Cc: Markus Armbruster > Cc: Paolo Bonzini > Signed-off-by: Murilo Opsfelder Araujo > --- > HACKING | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/HACKING b/HACKING > index 4125c97d8d..0fc3e0fc04 100644 > --- a/HACKING > +++ b/HACKING > @@ -118,6 +118,15 @@ Please note that g_malloc will exit on allocation failure, so there > is no need to test for failure (as you would have to with malloc). > Calling g_malloc with a zero size is valid and will return NULL. > > +Prefer g_new(T, n) instead of g_malloc(sizeof(T) * n) for the following > +reasons: Should we make this stronger? s/Prefer/Use/ ? Because I think that for this use case we have an agreement (sizeof(T) vs. sizeof(*var)). > + > + a. It catches multiplication overflowing size_t; > + b. It returns T * instead of void *, letting compiler catch more type > + errors. > + > +Declarations like T *v = g_malloc(sizeof(*v)) are acceptable, though. > + > Memory allocated by qemu_memalign or qemu_blockalign must be freed with > qemu_vfree, since breaking this will cause problems on Win32. > > This seems to be the right place to start documenting such stuff. Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb