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Fri, 17 Oct 2025 08:16:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760689016; bh=/nupFfiBDTK8f3z19X5zBCAoNMhBKwg/9yA8JDj7YJ8=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=ekUis2qS/K43Wa3oMb6pzVrmzyh0OGl14tcBxht+kGV+lez/llzNd0s9mNO0RzixN Q75JOdhNNo5UNgwXRxdAmWUi1TmKQfgq+e5PzKWDXtyivWCST/OSYnWJkfXMnb/O0F bWFd3BTr2YRTDY2ZsyW9T5wO/yvIT9f9cT9MABvo= Subject: Patch "minmax.h: update some comments" has been added to the 5.15-stable tree To: David.Laight@ACULAB.COM, Jason@zx2c4.com, adilger.kernel@dilger.ca, agk@redhat.com, airlied@linux.ie, akpm@linux-foundation.org, amd-gfx@lists.freedesktop.org, andriy.shevchenko@linux.intel.com, anton.ivanov@cambridgegreys.com, arnd@kernel.org, axboe@kernel.dk, bp@alien8.de, clm@fb.com, coreteam@netfilter.org, dan.carpenter@linaro.org, daniel@ffwll.ch, dave.hansen@linux.intel.com, davem@davemloft.net, david.laight@aculab.com, dm-devel@redhat.com, dmitry.torokhov@gmail.com, dri-devel@lists.freedesktop.org, dsahern@kernel.org, dsterba@suse.com, dushistov@mail.ru, farbere@amazon.com, freedreno@lists.freedesktop.org, fw@strlen.de, gregkh@linuxfoundation.org, hch@infradead.org, hdegoede@redhat.com, herve.codina@bootlin.com, hpa@zytor.com, jack@suse.com, james.morse@arm.com, jdelvare@suse.com, jdike@addtoit.com, jejb@linux.ibm.com, jernej.skrabec@gmail.com, jmaloy@redhat.com, josef@toxicpanda.com, kadlec@netfilter.org, krzysztof.kozlowski@canonical.com, kuba@kernel.org, linus.walleij@linaro.org, linux-arm-kernel@lists.infradead.o, rg@kvack.org, linux-mm@kvack.org, linux-staging@lists.linux.dev, linux-stm32@st-md-mailman.stormreply.com, linux-sunxi@lists.linux.dev, linux-um@lists.infradead.org, linux@rasmusvillemoes.dk, linux@roeck-us.net, lorenzo.stoakes@oracle.com, luc.vanoostenryck@gmail.com, luto@kernel.org, maarten.lankhorst@linux.intel.com, malattia@linux.it, martin.petersen@oracle.com, maz@kernel.org, mcoquelin.stm32@gmail.com, mgross@linux.intel.com, minchan@kernel.org, mingo@redhat.com, mjguzik@gmail.com, mripard@kernel.org, ngupta@vflare.org, pablo@netfilter.org, pedro.falcato@gmail.com, peterz@infradead.org, pmladek@suse.com, qiuxu.zhuo@intel.com, quic_akhilpo@quicinc.com, richard@nod.at, robdclark@gmail.com, rostedt@goodmis.org, rric@kernel.org, ruanjinjie@huawei.com, sakari.ailus@linux.intel.com, sashal@kernel.org, sean@poorly.run, senozhatsky@chromium.org, shuah@kernel.org, snitzer@redhat.com, tglx@linutronix.de, tipc-discussion@lists.sourceforge.net, tony.luck@intel.com, tytso@mit.edu, tzimmermann@suse.de, wens@csie.org, willy@infradead.org, x86@kern.kvack.org, el.org@kvack.org, ying.xue@windriver.com, yoshfuji@linux-ipv6.org Cc: From: Date: Fri, 17 Oct 2025 10:16:20 +0200 In-Reply-To: <20251008152946.29285-15-farbere@amazon.com> Message-ID: <2025101720-splashed-matriarch-b59d@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit X-stable: commit X-Patchwork-Hint: ignore X-Rspamd-Queue-Id: 8A6361C0006 X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: wytnuky45u6jbptc7sqyqrzrwhdqysi4 X-HE-Tag: 1760689017-837197 X-HE-Meta: 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 QkADefpT quBHJgkYomCFolL2SafxIz3izhzb9OYwe1DVK90J4+09JoDeb0O+odfzIMIZmF9hUFWZIPlg4MVoIlWI4L729XkBbxvWH4MA2ax4jAcRaCIbqvKRQP0Yol4E0GYuu5zjKjLFW09iOJpCp5hU11SOxRjxShg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: This is a note to let you know that I've just added the patch titled minmax.h: update some comments to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: minmax.h-update-some-comments.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From prvs=36971892a=farbere@amazon.com Wed Oct 8 17:34:21 2025 From: Eliav Farber Date: Wed, 8 Oct 2025 15:29:39 +0000 Subject: minmax.h: update some comments To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Cc: Arnd Bergmann , Christoph Hellwig , Dan Carpenter , "Jason A. Donenfeld" , Jens Axboe , Lorenzo Stoakes , Mateusz Guzik , "Pedro Falcato" Message-ID: <20251008152946.29285-15-farbere@amazon.com> 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 Signed-off-by: Greg Kroah-Hartman --- include/linux/minmax.h | 61 ++++++++++++++++++++++--------------------------- 1 file changed, 28 insertions(+), 33 deletions(-) --- 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 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). - * - * 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. + * 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. + * + * 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. */ #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). - * - * NOTE! The cast is there only to avoid any warnings - * from when values that aren't signed integer types. + * 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. + * + * 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 Patches currently in stable-queue which might be from farbere@amazon.com are queue-5.15/minmax-add-a-few-more-min_t-max_t-users.patch queue-5.15/minmax-improve-macro-expansion-and-type-checking.patch queue-5.15/minmax-fix-indentation-of-__cmp_once-and-__clamp_once.patch queue-5.15/minmax.h-simplify-the-variants-of-clamp.patch queue-5.15/minmax-add-in_range-macro.patch queue-5.15/minmax.h-move-all-the-clamp-definitions-after-the-min-max-ones.patch queue-5.15/minmax-don-t-use-max-in-situations-that-want-a-c-constant-expression.patch queue-5.15/minmax.h-remove-some-defines-that-are-only-expanded-once.patch queue-5.15/minmax.h-use-build_bug_on_msg-for-the-lo-hi-test-in-clamp.patch queue-5.15/minmax-simplify-min-max-clamp-implementation.patch queue-5.15/minmax-deduplicate-__unconst_integer_typeof.patch queue-5.15/minmax-simplify-and-clarify-min_t-max_t-implementation.patch queue-5.15/minmax.h-add-whitespace-around-operators-and-after-commas.patch queue-5.15/minmax-avoid-overly-complicated-constant-expressions-in-vm-code.patch queue-5.15/minmax-make-generic-min-and-max-macros-available-everywhere.patch queue-5.15/minmax-fix-up-min3-and-max3-too.patch queue-5.15/minmax.h-reduce-the-define-expansion-of-min-max-and-clamp.patch queue-5.15/minmax-introduce-min-max-_array.patch queue-5.15/minmax.h-update-some-comments.patch