From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9F772CCA471 for ; Fri, 3 Oct 2025 12:17:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0AzpApDbX8CFEbC2P7WHNPH2gra+XDIh1eSQ6GUhJZw=; b=M5FIZQI+rQSCfVrVRpjzltxDA1 nAbjPO5ycuLgn8vxgQgilHaj80r3qDRP633KXqD+/JdwHc+DwpjfZUx5VLan501xleH88R2MvsDhK rZoiT6OPx3EmNzmm1y/Xn2c5jd5+W4dsiCjfjM81Aeh6+cLgWck7RgKIetHwvcoC3BdtXO3pYSY4t iVvpukdzQiYUCIx7RM6RQbWlmpQOWMowLUWxvnbjhiabE/3x03w3XaWmJ0Yk/zQ4JHWswh6sZbh2n /CpI69Olg7VmsJUfuBNneomJODzO389uXFOzV9jQ7lVjsfDJrI0r8Js0s7fUYggxemkPXkvVx1rjA f6QR8VyQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v4eim-0000000CFnd-2OmO; Fri, 03 Oct 2025 12:17:12 +0000 Received: from fra-out-005.esa.eu-central-1.outbound.mail-perimeter.amazon.com ([63.176.194.123]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v4eij-0000000CFkq-3QeJ for linux-arm-kernel@lists.infradead.org; Fri, 03 Oct 2025 12:17:11 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1759493829; x=1791029829; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=0AzpApDbX8CFEbC2P7WHNPH2gra+XDIh1eSQ6GUhJZw=; b=dn7k5UI/DgP4ArQ36gleWWVtO1kbalXT+63G0Dre2LQfbhigiJSmZbDD xnbTJ9MKTLqWfmUuiWpsufTjGCrguD/ulGmaUGGtCI8sXRpsHpZsfcXVT kKOBzvTJI9ZM98CgKekk0XK7gN1ia2MxtOH1SLTLZEiLiglNz6x1ctqBT KF6Cvtd7mg7PhcF/qoD355rzMbwKqxR5oVqtsKDTm2B05G7Qpenpv6FQi xrnQXOggyTqM6bdVHVFG6CnHSPrwNBn0sqirCZlzkr2Kyhbg4f1Aa6/5f 5bCriwlFXo8nh1eTRm5gJHqspF/BUYE9dHCfFo6+Zra3jUb25MCo/7H5G g==; X-CSE-ConnectionGUID: GF5Gm469RGCFWfNBuSrp0A== X-CSE-MsgGUID: Ky/l0fQHTlGTysDjZi+xig== X-IronPort-AV: E=Sophos;i="6.18,312,1751241600"; d="scan'208";a="3060308" 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-005.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Oct 2025 12:16:59 +0000 Received: from EX19MTAEUC001.ant.amazon.com [54.240.197.225:4398] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.33.147:2525] with esmtp (Farcaster) id 051d7b3e-dad6-4b7d-bec9-faaa743d62e1; Fri, 3 Oct 2025 12:16:59 +0000 (UTC) X-Farcaster-Flow-ID: 051d7b3e-dad6-4b7d-bec9-faaa743d62e1 Received: from EX19D018EUA004.ant.amazon.com (10.252.50.85) by EX19MTAEUC001.ant.amazon.com (10.252.51.193) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.20; Fri, 3 Oct 2025 12:16:58 +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, 3 Oct 2025 12:16:46 +0000 From: Eliav Farber To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , CC: Arnd Bergmann , Christoph Hellwig , Dan Carpenter , "Jason A. Donenfeld" , Jens Axboe , Lorenzo Stoakes , Mateusz Guzik , "Matthew Wilcox" , Pedro Falcato Subject: [PATCH v4 06/11 6.1.y] minmax.h: update some comments Date: Fri, 3 Oct 2025 12:15:15 +0000 Message-ID: <20251003121520.8176-7-farbere@amazon.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251003121520.8176-1-farbere@amazon.com> References: <20251003121520.8176-1-farbere@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [172.19.116.181] X-ClientProxiedBy: EX19D045UWC001.ant.amazon.com (10.13.139.223) To EX19D018EUA004.ant.amazon.com (10.252.50.85) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251003_051710_131921_0AAC3409 X-CRM114-Status: GOOD ( 24.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: David Laight [ Upstream commit 10666e99204818ef45c702469488353b5bb09ec7 ] - Change three to several. - Remove the comment about retaining constant expressions, no longer true. - Realign to nearer 80 columns and break on major punctiation. - Add a leading comment to the block before __signed_type() and __is_nonneg() Otherwise the block explaining the cast is a bit 'floating'. Reword the rest of that comment to improve readability. Link: https://lkml.kernel.org/r/85b050c81c1d4076aeb91a6cded45fee@AcuMS.aculab.com Signed-off-by: David Laight Cc: Andy Shevchenko Cc: Arnd Bergmann Cc: Christoph Hellwig Cc: Dan Carpenter Cc: Jason A. Donenfeld Cc: Jens Axboe Cc: Lorenzo Stoakes Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Pedro Falcato Signed-off-by: Andrew Morton Signed-off-by: Eliav Farber --- include/linux/minmax.h | 53 +++++++++++++++++++----------------------- 1 file changed, 24 insertions(+), 29 deletions(-) diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 51b0d988e322..24e4b372649a 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -8,13 +8,10 @@ #include /* - * min()/max()/clamp() macros must accomplish three things: + * min()/max()/clamp() macros must accomplish several things: * * - Avoid multiple evaluations of the arguments (so side-effects like * "x++" happen only once) when non-constant. - * - 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 @@ -31,25 +28,23 @@ * bit #0 set if ok for unsigned comparisons * bit #1 set if ok for signed comparisons * - * In particular, statically non-negative signed integer - * expressions are ok for both. + * In particular, statically non-negative signed integer expressions + * are ok for both. * - * NOTE! Unsigned types smaller than 'int' are implicitly - * converted to 'int' in expressions, and are accepted for - * signed conversions for now. This is debatable. + * NOTE! Unsigned types smaller than 'int' are implicitly converted to 'int' + * in expressions, and are accepted for signed conversions for now. + * This is debatable. * - * Note that 'x' is the original expression, and 'ux' is - * the unique variable that contains the value. + * Note that 'x' is the original expression, and 'ux' is the unique variable + * that contains the value. * - * We use 'ux' for pure type checking, and 'x' for when - * we need to look at the value (but without evaluating - * it for side effects! Careful to only ever evaluate it - * with sizeof() or __builtin_constant_p() etc). + * We use 'ux' for pure type checking, and 'x' for when we need to look at the + * value (but without evaluating it for side effects! + * Careful to only ever evaluate it with sizeof() or __builtin_constant_p() etc). * - * Pointers end up being checked by the normal C type - * rules at the actual comparison, and these expressions - * only need to be careful to not cause warnings for - * pointer use. + * Pointers end up being checked by the normal C type rules at the actual + * comparison, and these expressions only need to be careful to not cause + * warnings for pointer use. */ #define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux)) #define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4)) @@ -57,19 +52,19 @@ __signed_type_use(x, ux) : __unsigned_type_use(x, ux)) /* - * To avoid warnings about casting pointers to integers - * of different sizes, we need that special sign type. + * Check whether a signed value is always non-negative. * - * On 64-bit we can just always use 'long', since any - * integer or pointer type can just be cast to that. + * A cast is needed to avoid any warnings from values that aren't signed + * integer types (in which case the result doesn't matter). * - * This does not work for 128-bit signed integers since - * the cast would truncate them, but we do not use s128 - * types in the kernel (we do use 'u128', but they will - * be handled by the !is_signed_type() case). + * On 64-bit any integer or pointer type can safely be cast to 'long'. + * But on 32-bit we need to avoid warnings about casting pointers to integers + * of different sizes without truncating 64-bit values so 'long' or 'long long' + * must be used depending on the size of the value. * - * NOTE! The cast is there only to avoid any warnings - * from when values that aren't signed integer types. + * This does not work for 128-bit signed integers since the cast would truncate + * them, but we do not use s128 types in the kernel (we do use 'u128', + * but they are handled by the !is_signed_type() case). */ #ifdef CONFIG_64BIT #define __signed_type(ux) long -- 2.47.3