From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42887) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIIsU-0007UK-13 for qemu-devel@nongnu.org; Tue, 06 Jun 2017 14:06:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dIIsQ-0001Kr-Ss for qemu-devel@nongnu.org; Tue, 06 Jun 2017 14:06:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52790) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dIIsQ-0001KX-Mb for qemu-devel@nongnu.org; Tue, 06 Jun 2017 14:06:46 -0400 Date: Tue, 6 Jun 2017 21:06:42 +0300 From: "Michael S. Tsirkin" Message-ID: <20170606210555-mutt-send-email-mst@kernel.org> References: <20170606182354-mutt-send-email-mst@kernel.org> <87efuxjdpx.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87efuxjdpx.fsf@dusky.pond.sub.org> Subject: Re: [Qemu-devel] [PATCH v2 1/6] pci: Clean up error checking in pci_add_capability() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Mao Zhongyi , marcel@redhat.com, qemu-devel@nongnu.org On Tue, Jun 06, 2017 at 06:14:02PM +0200, Markus Armbruster wrote: > "Michael S. Tsirkin" writes: > > > On Fri, Jun 02, 2017 at 03:54:37PM +0800, Mao Zhongyi wrote: > >> On success, pci_add_capability2() returns a positive value. On > >> failure, it sets an error and return a negative value. > >> > >> pci_add_capability() laboriously checks this behavior. No other > >> caller does. Drop the checks from pci_add_capability(). > >> > >> Cc: mst@redhat.com > >> Cc: marcel@redhat.com > >> Cc: armbru@redhat.com > >> Signed-off-by: Mao Zhongyi > >> Reviewed-by: Marcel Apfelbaum > >> --- > >> hw/pci/pci.c | 6 +----- > >> 1 file changed, 1 insertion(+), 5 deletions(-) > >> > >> diff --git a/hw/pci/pci.c b/hw/pci/pci.c > >> index 98ccc27..53566b8 100644 > >> --- a/hw/pci/pci.c > >> +++ b/hw/pci/pci.c > >> @@ -2270,12 +2270,8 @@ int pci_add_capability(PCIDevice *pdev, uint8_t cap_id, > >> Error *local_err = NULL; > >> > >> ret = pci_add_capability2(pdev, cap_id, offset, size, &local_err); > >> - if (local_err) { > >> - assert(ret < 0); > >> + if (ret < 0) { > >> error_report_err(local_err); > >> - } else { > >> - /* success implies a positive offset in config space */ > >> - assert(ret > 0); > >> } > >> return ret; > >> } > > > > > > I don't see why this is a good idea. You drop a bunch of > > asserts, so naturally code is slightly tighter. We could gain > > the same by building with NDEBUG but we don't, we rather > > have more safety. > > It's a good idea because it's what we do basically everywhere when a > function sets an error and returns a distinct error value. We typically just do if (local_err) { error_report_err(local_err); ... }