From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Wolf Subject: Re: [Qemu-devel] [PATCH] Introduce QEMU_NEW() Date: Mon, 25 Jul 2011 12:25:16 +0200 Message-ID: <4E2D448C.9030306@redhat.com> References: <1311583872-362-1-git-send-email-avi@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , qemu-devel@nongnu.org, kvm@vger.kernel.org To: Stefan Hajnoczi Return-path: Received: from mx1.redhat.com ([209.132.183.28]:22923 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751579Ab1GYKWX (ORCPT ); Mon, 25 Jul 2011 06:22:23 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: Am 25.07.2011 12:06, schrieb Stefan Hajnoczi: > On Mon, Jul 25, 2011 at 9:51 AM, Avi Kivity wrote: >> qemu_malloc() is type-unsafe as it returns a void pointer. Introduce >> QEMU_NEW() (and QEMU_NEWZ()), which return the correct type. >> >> Signed-off-by: Avi Kivity >> --- >> >> This is part of my memory API patchset, but doesn't really belong there. >> >> qemu-common.h | 3 +++ >> 1 files changed, 3 insertions(+), 0 deletions(-) >> >> diff --git a/qemu-common.h b/qemu-common.h >> index ba55719..66effa3 100644 >> --- a/qemu-common.h >> +++ b/qemu-common.h >> @@ -186,6 +186,9 @@ void qemu_free(void *ptr); >> char *qemu_strdup(const char *str); >> char *qemu_strndup(const char *str, size_t size); >> >> +#define QEMU_NEW(type) ((type *)(qemu_malloc(sizeof(type)))) >> +#define QEMU_NEWZ(type) ((type *)(qemu_mallocz(sizeof(type)))) > > Does this mean we need to duplicate the type name for each allocation? > > struct foo *f; > > ... > f = qemu_malloc(sizeof(*f)); > > Becomes: > > struct foo *f; > > ... > f = QEMU_NEW(struct foo); Maybe we should allow this and make it the usual pattern: f = qemu_new(typeof(*f)); It's gcc specific, but we already don't care about portability to other compilers in more places. On the other hand, how many bugs did we have recently that were caused by a wrong sizeof for qemu_malloc? As far as I can say, there's no real reason to do it. I think it's the same kind of discussion as with forbidding qemu_malloc(0) (except that this time it just won't improve things much instead of being really stupid). Kevin