From nobody Thu Oct 2 09:19:24 2025 Received: from fra-out-014.esa.eu-central-1.outbound.mail-perimeter.amazon.com (fra-out-014.esa.eu-central-1.outbound.mail-perimeter.amazon.com [18.199.210.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D1954212566; Fri, 19 Sep 2025 10:24:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=18.199.210.3 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758277474; cv=none; b=AFRBgn739moovfQNmVag2GyKc5YE+XQ8qaaxJoN5eUZXlo7yD5pvhUsvdRK9bLbZRXk1ALgD0D1mYyGFZB5h3thnRQou/sjuxrfsm2MwdnltpHXjRwGtwglyEEh3WXJ0rGxgGrxPdvzvmCHpqXnBk0jdDJ5IUOEVs0Q9gbFMqa0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758277474; c=relaxed/simple; bh=OMdwAX0D4RWxyOV+A/UOqWcXqJeRVU0cG+oVZfFnsG4=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hlsxdLxLVy6qBaicqC4bHdNsbDHvtTsO4Twwl/oc3LEw9dlZ3n08lJfRlezUPJk5SBretVKt/V4jBY7gjaQ52vRzuICs+pIvZ3lr93SGFIjhOJ5Sc91unXPRoKOyKzHHBtRHMRHuDfRSDnpMczTxgb51okzzwqvpmrNY3E/2ACU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=qvEbABwe; arc=none smtp.client-ip=18.199.210.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="qvEbABwe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1758277472; x=1789813472; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Up26bfkjgG7bBpXTUDNOne3Gaz9xL27H6G5Ic5zP1jo=; b=qvEbABwe2zrrjJtz9XZK+Wd3DAxchcHdm/TUPATx65fexPZCneVrcPio WxvAPsjuG42ebzT2PYJsy8oJ7fdL1V5VYROTwCPvLZMDP39uLtnvcUn1+ AhM14p5IrGRcz7ABNy+34bL6Qmxfe5aUhWzI7Yo1vSsvhJ3rWO9ISI7wt IGLfqkRnc4uqqlh4NPDPvlhAFly9EoPU1oxqHHI/YDJvT7N7z0VJsZ5NV eKNt5iTte4oRtxFHy+9CiH2HwLImB28soIUdfWXHyH3dBAJykj53oVFBo M8HGmsA1hdSo/a11r8XUvBXqkfwdb+MwiyUB5qGButEnvhsygjaRuEgH1 g==; X-CSE-ConnectionGUID: uOA4YP9ESZq1z3U+/FQblQ== X-CSE-MsgGUID: +9AKtw6XT7ywoAOd2DOyxg== X-IronPort-AV: E=Sophos;i="6.18,277,1751241600"; d="scan'208";a="2264848" Received: from ip-10-6-6-97.eu-central-1.compute.internal (HELO smtpout.naws.eu-central-1.prod.farcaster.email.amazon.dev) ([10.6.6.97]) by internal-fra-out-014.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2025 10:24:21 +0000 Received: from EX19MTAEUA002.ant.amazon.com [54.240.197.232:12085] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.23.64:2525] with esmtp (Farcaster) id 13c390b8-4d66-4da4-9902-c277754da027; Fri, 19 Sep 2025 10:24:21 +0000 (UTC) X-Farcaster-Flow-ID: 13c390b8-4d66-4da4-9902-c277754da027 Received: from EX19D018EUA004.ant.amazon.com (10.252.50.85) by EX19MTAEUA002.ant.amazon.com (10.252.50.126) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.20; Fri, 19 Sep 2025 10:24:18 +0000 Received: from dev-dsk-farbere-1a-46ecabed.eu-west-1.amazon.com (172.19.116.181) by EX19D018EUA004.ant.amazon.com (10.252.50.85) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.20; Fri, 19 Sep 2025 10:23:50 +0000 From: Eliav Farber To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , CC: , Christoph Hellwig , Linus Torvalds Subject: [PATCH 11/27 5.10.y] minmax: relax check to allow comparison between unsigned arguments and signed constants Date: Fri, 19 Sep 2025 10:17:11 +0000 Message-ID: <20250919101727.16152-12-farbere@amazon.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20250919101727.16152-1-farbere@amazon.com> References: <20250919101727.16152-1-farbere@amazon.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: EX19D032UWA003.ant.amazon.com (10.13.139.37) To EX19D018EUA004.ant.amazon.com (10.252.50.85) Content-Type: text/plain; charset="utf-8" From: David Laight [ Upstream commit 867046cc7027703f60a46339ffde91a1970f2901 ] Allow (for example) min(unsigned_var, 20). The opposite min(signed_var, 20u) is still errored. Since a comparison between signed and unsigned never makes the unsigned value negative it is only necessary to adjust the __types_ok() test. Link: https://lkml.kernel.org/r/633b64e2f39e46bb8234809c5595b8c7@AcuMS.acul= ab.com Signed-off-by: David Laight Cc: Andy Shevchenko Cc: Christoph Hellwig Cc: Jason A. Donenfeld Cc: Linus Torvalds Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Signed-off-by: Eliav Farber --- include/linux/minmax.h | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 842c1db62ffe..2ec559284a9f 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -10,13 +10,18 @@ /* * min()/max()/clamp() macros must accomplish three things: * - * - avoid multiple evaluations of the arguments (so side-effects like + * - Avoid multiple evaluations of the arguments (so side-effects like * "x++" happen only once) when non-constant. - * - perform signed v unsigned type-checking (to generate compile - * errors instead of nasty runtime surprises). - * - retain result as a constant expressions when called with only + * - Retain result as a constant expressions when called with only * constant expressions (to avoid tripping VLA warnings in stack * allocation usage). + * - Perform signed v unsigned type-checking (to generate compile + * errors instead of nasty runtime surprises). + * - Unsigned char/short are always promoted to signed int and can be + * compared against signed or unsigned arguments. + * - Unsigned arguments can be compared against non-negative signed consta= nts. + * - Comparison of a signed argument against an unsigned constant fails + * even if the constant is below __INT_MAX__ and could be cast to int. */ #define __typecheck(x, y) \ (!!(sizeof((typeof(x) *)1 =3D=3D (typeof(y) *)1))) @@ -26,9 +31,14 @@ __builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))), \ is_signed_type(typeof(x)), 0) =20 -#define __types_ok(x, y) \ - (__is_signed(x) =3D=3D __is_signed(y) || \ - __is_signed((x) + 0) =3D=3D __is_signed((y) + 0)) +/* True for a non-negative signed int constant */ +#define __is_noneg_int(x) \ + (__builtin_choose_expr(__is_constexpr(x) && __is_signed(x), x, -1) >=3D 0) + +#define __types_ok(x, y) \ + (__is_signed(x) =3D=3D __is_signed(y) || \ + __is_signed((x) + 0) =3D=3D __is_signed((y) + 0) || \ + __is_noneg_int(x) || __is_noneg_int(y)) =20 #define __cmp_op_min < #define __cmp_op_max > --=20 2.47.3