From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fra-out-008.esa.eu-central-1.outbound.mail-perimeter.amazon.com (fra-out-008.esa.eu-central-1.outbound.mail-perimeter.amazon.com [35.158.23.94]) (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 55957307487; Fri, 19 Sep 2025 10:24:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=35.158.23.94 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758277467; cv=none; b=HD2sQ5SUJHBiiV1bTiwf93sgXDqOWO72XudlFFkGuTSElJFAq5thTnNEEIwun6bKDTBUrbfLMCpSQnjMSHjVB4dqMeXSDcpB7WI9NmTWj9xTtmMIwJGca5bz6VFt4zAzvTdvTrbqgRhZYXbg2IP2wEJQD47VlUzeBTkRzgFO63E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758277467; 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=kXeLdHaVIkzm6NLxbS3tCuAn5MJyIsTfj8FThSM58l/77BHzhBsEfUu2y7xyr0EfH8SrupGngw+WnU4Ynmfs/bUBxe6ZX9IsoPMcvuInclSLJE9eiNW25rEx3FLdEthz5hzcEbqligI1NWZj4PuDmCxzTYLxj1MJO09xqrvSKHM= 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=rxUEAIFf; arc=none smtp.client-ip=35.158.23.94 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="rxUEAIFf" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1758277465; x=1789813465; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Up26bfkjgG7bBpXTUDNOne3Gaz9xL27H6G5Ic5zP1jo=; b=rxUEAIFfiZKNeSuA17eoiicaKLk7XoNMr0fpONx9ELuK0oT2XvtUph5R i6zw62WmIdlTA8BtBAWx22eipSAQ5jK1teZbkD0YX0Maj4riFuLdQDjEZ oe+uuai+y+LgdoZ11gSexnA66bXuWnav6Ncr0bZqdvbhymGeZryexpSM3 NW+G5aqMy4xegOwCxtFq720K9UN7vv7qmSnFC9HqPjyAcE5JqFRsfWT0X zBV7c3DzE2u8V+tf5LAxuBvmkD+6JPMPQAON+olHG54ZCSJ3MHJ/HidYJ 4kE5ag+VC1kLhmctyRqh1dKVthJuRN1D2h6/X0oeLKe3Ny493VReWpj1V w==; X-CSE-ConnectionGUID: VfUMBUH0R+udyi3y5h9lpA== X-CSE-MsgGUID: fEXY14+oTR2Ji22+/AcC7g== X-IronPort-AV: E=Sophos;i="6.18,277,1751241600"; d="scan'208";a="2371767" 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-008.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2025 10:24:22 +0000 Received: from EX19MTAEUA002.ant.amazon.com [54.240.197.232:21608] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.8.212:2525] with esmtp (Farcaster) id 504dbbff-7d1b-49bf-9922-7914909fe636; Fri, 19 Sep 2025 10:24:22 +0000 (UTC) X-Farcaster-Flow-ID: 504dbbff-7d1b-49bf-9922-7914909fe636 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-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: EX19D032UWA003.ant.amazon.com (10.13.139.37) To EX19D018EUA004.ant.amazon.com (10.252.50.85) 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.aculab.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 constants. + * - 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 == (typeof(y) *)1))) @@ -26,9 +31,14 @@ __builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))), \ is_signed_type(typeof(x)), 0) -#define __types_ok(x, y) \ - (__is_signed(x) == __is_signed(y) || \ - __is_signed((x) + 0) == __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) >= 0) + +#define __types_ok(x, y) \ + (__is_signed(x) == __is_signed(y) || \ + __is_signed((x) + 0) == __is_signed((y) + 0) || \ + __is_noneg_int(x) || __is_noneg_int(y)) #define __cmp_op_min < #define __cmp_op_max > -- 2.47.3