From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="VEaBr5MD" Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4001197 for ; Tue, 21 Nov 2023 04:26:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=YbnoFbHOJP34t98n8U9xwnthCBmbFv/PCkdcF4geYfE=; b=VEaBr5MDsdTaZkklfcru5V5N02 mCvvR1hAk1cYeQllDatwRfHux8cZ5hw8LTB+PZkj71of+mPTI8bYWURLDP9H/DKkyeKV0VLz+zEiK +EZtVOizhPjO9LkkDA6FZJOJ+iHPuGXCB0kUUqEK0G4/+Z7ZxZbkE56nCg9LkxDD+Lm1HPTwJHLvW 2M02SI2nvEnVPEoctI+QQrDVsMQ/e0185hnoap1BDproR2tSVUnVkIvnf8hlQlH+m0KrcFjcxmGS+ puJgFNkYYWluTZlNnn8CWf7N7YluR0ArbPIsPq35JxAR5ISv5i+wUc4Q25srXHftivbtA8/0h7rMl BQfKbk0A==; Received: from [2001:8b0:10b:5:9608:1c8b:df8c:28f9] (helo=u3832b3a9db3152.ant.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1r5PpE-005ZwI-AI; Tue, 21 Nov 2023 12:25:56 +0000 Message-ID: <708be5bf6573aadb73f9ac1be4a3adae304586c3.camel@infradead.org> Subject: Re: [PATCH 06/12] hw/xen: add get_frontend_path() method to XenDeviceClass From: David Woodhouse To: paul@xen.org, qemu-devel@nongnu.org Cc: Kevin Wolf , Hanna Reitz , Stefano Stabellini , Anthony Perard , =?ISO-8859-1?Q?Marc-Andr=E9?= Lureau , Paolo Bonzini , "Michael S. Tsirkin" , Marcel Apfelbaum , Richard Henderson , Eduardo Habkost , Marcelo Tosatti , qemu-block@nongnu.org, xen-devel@lists.xenproject.org, kvm@vger.kernel.org Date: Tue, 21 Nov 2023 12:25:55 +0000 In-Reply-To: <4d059cb96a92004fe25fdb140a6c0b12e91b4d7e.camel@infradead.org> References: <20231016151909.22133-1-dwmw2@infradead.org> <20231016151909.22133-7-dwmw2@infradead.org> <5ef43a7c-e535-496d-8a14-bccbadab3bc0@xen.org> <55bb6967-9499-45ef-b4c8-00fbfaccef0d@xen.org> <4d059cb96a92004fe25fdb140a6c0b12e91b4d7e.camel@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-3F9/wyoYYAMsi6WYTL8o" User-Agent: Evolution 3.44.4-0ubuntu2 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html --=-3F9/wyoYYAMsi6WYTL8o Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2023-10-24 at 14:29 +0100, David Woodhouse wrote: >=20 > > > As a general rule (I'll be doing a bombing run on xen-bus once I get = my > > > patch queue down into single digits) we should never check 'if (*errp= )' > > > to check if a function had an error. It should *also* return a succes= s > > > or failure indication, and we should cope with errp being NULL. > > >=20 > >=20 > > I'm pretty sure someone told me the exact opposite a few years back. >=20 > Then they were wrong :) cf. https://gitlab.com/qemu-project/qemu/-/commit/e3fe3988d7 "Whenever practical, also return a value that indicates success / failure" --=-3F9/wyoYYAMsi6WYTL8o Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEkQw ggYQMIID+KADAgECAhBNlCwQ1DvglAnFgS06KwZPMA0GCSqGSIb3DQEBDAUAMIGIMQswCQYDVQQG EwJVUzETMBEGA1UECBMKTmV3IEplcnNleTEUMBIGA1UEBxMLSmVyc2V5IENpdHkxHjAcBgNVBAoT FVRoZSBVU0VSVFJVU1QgTmV0d29yazEuMCwGA1UEAxMlVVNFUlRydXN0IFJTQSBDZXJ0aWZpY2F0 aW9uIEF1dGhvcml0eTAeFw0xODExMDIwMDAwMDBaFw0zMDEyMzEyMzU5NTlaMIGWMQswCQYDVQQG EwJHQjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxmb3JkMRgwFgYD 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