From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from bues.ch ([80.190.117.144]:37190 "EHLO bues.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751014AbbKZNea (ORCPT ); Thu, 26 Nov 2015 08:34:30 -0500 Date: Thu, 26 Nov 2015 14:34:16 +0100 From: Michael =?UTF-8?B?QsO8c2No?= To: Dan Carpenter Cc: linux-wireless@vger.kernel.org, b43-dev@lists.infradead.org Subject: Re: (bug report) b43: impossible conditions in debugfs Message-ID: <20151126143416.6104ff24@wiggum> (sfid-20151126_143432_906645_72E64090) In-Reply-To: <20151126130033.GG7289@mwanda> References: <20151126115924.GI10556@mwanda> <20151126133241.5bc5a793@wiggum> <20151126130033.GG7289@mwanda> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; boundary="Sig_/glKQgqGoGSN9PWrx0FRzTYm"; protocol="application/pgp-signature" Sender: linux-wireless-owner@vger.kernel.org List-ID: --Sig_/glKQgqGoGSN9PWrx0FRzTYm Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Thu, 26 Nov 2015 16:00:34 +0300 Dan Carpenter wrote: > On Thu, Nov 26, 2015 at 01:32:41PM +0100, Michael B=C3=BCsch wrote: > > > See also: > > > drivers/net/wireless/broadcom/b43/debugfs.c:346 mmio32write__write_fi= le() warn: impossible condition '(mask > 4294967295) =3D> (0-u32max > u32ma= x)' > > > drivers/net/wireless/broadcom/b43/debugfs.c:346 mmio32write__write_fi= le() warn: impossible condition '(set > 4294967295) =3D> (0-u32max > u32max= )' =20 > >=20 > >=20 > >=20 > > Sure. These are intentional. > > The compiler will optimize this out. =20 >=20 > Hm... We try to ignore when people do intentional comparisons with zero > like this: >=20 > if (unsigned_var < 0 || unsigned_var >=3D 10) > return -EINVAL; >=20 > Because they are obviously harmless and they don't hurt readability. > Also Linus doesn't like removing these. It just checks whether the value will fit into a 32 bit unsigned int variable. It doesn't make assumptions on what sizeof(unsigned int) is, although it would be safe to assume 4 here and omit the check. --=20 Michael --Sig_/glKQgqGoGSN9PWrx0FRzTYm Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJWVwpYAAoJEPUyvh2QjYsOdzwP/j1/FXqsbLmnp03ZLv29XnNm F5AghFPpc/4qEWpEWdxCoQ623elFqE31c8kifoXxzqml2LlIiWQTJKfPrpPbl+7d IFRdCvq2jI54IsthwqKNBynNP6+IpYZSf+iYs1cZwi37VhmTZQcriGDlp/teQDK5 ZF4qCxJ5YizrKd22XYHLiyoHTgMlzGqeUTmkkRXzSd4xlWc/B8KL2S5Nvk/SNL2P 0Xa8WC1J430jNv1eppSeaXCBnElLg5EO4bhaezCeprl5hqunwSFMUhqA7FAkHdup G3DclgwcNJhT818NLWZ5Oft0w4blbpn6g/5Ma2d12UhQv47iwvwD37mULZOzpok0 VFyxVB1bX3NWFN13jp4VRPbZ/bcHRnihRGFU+ezkO9BR8MsI/p9pGGQ4/+23Fic/ Asepe4wBT9eNTQpKuJ4uik0lWfVQk5s5Ehp2psfNuIsKKeHfu3CGQ74NPCo6Lg9R AWQwBIqHTczO8NJxoeuouQ/KRnql6Rx4B7sAcIWDJCDY3Ef79wVMjT1iA6VoHJiU I4Epax7ql/E+vrvwbDdLLIIGLR5jtzgNWVfDKq8zu59H1zVmr0exgm51sf8O588c NzflA9qAakKiWNe/ghl0NAUAiuhg0TY/9VQ/LdDp+Y//MaAow2bawRa40FRFyRXR 2CgfXRSrxJgi68x7FfzH =jyLE -----END PGP SIGNATURE----- --Sig_/glKQgqGoGSN9PWrx0FRzTYm--