Patch "minmax: Introduce {min,max}_array()" has been added to the 5.10-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    minmax: Introduce {min,max}_array()

to the 5.10-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-introduce-min-max-_array.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From prvs=378230090=farbere@amazon.com Fri Oct 17 11:07:34 2025
From: Eliav Farber <farbere@amazon.com>
Date: Fri, 17 Oct 2025 09:04:58 +0000
Subject: minmax: Introduce {min,max}_array()
To: <gregkh@linuxfoundation.org>, <stable@vger.kernel.org>, <linux@armlinux.org.uk>, <jdike@addtoit.com>, <richard@nod.at>, <anton.ivanov@cambridgegreys.com>, <dave.hansen@linux.intel.com>, <luto@kernel.org>, <peterz@infradead.org>, <tglx@linutronix.de>, <mingo@redhat.com>, <bp@alien8.de>, <x86@kernel.org>, <hpa@zytor.com>, <tony.luck@intel.com>, <qiuxu.zhuo@intel.com>, <mchehab@kernel.org>, <james.morse@arm.com>, <rric@kernel.org>, <harry.wentland@amd.com>, <sunpeng.li@amd.com>, <alexander.deucher@amd.com>, <christian.koenig@amd.com>, <airlied@linux.ie>, <daniel@ffwll.ch>, <evan.quan@amd.com>, <james.qian.wang@arm.com>, <liviu.dudau@arm.com>, <mihail.atanassov@arm.com>, <brian.starkey@arm.com>, <maarten.lankhorst@linux.intel.com>, <mripard@kernel.org>, <tzimmermann@suse.de>, <robdclark@gmail.com>, <sean@poorly.run>, <jdelvare@suse.com>, <linux@roeck-us.net>, <fery@cypress.com>, <dmitry.torokhov@gmail.com>, <agk@redhat.com>, <snitzer@redhat.com>, <dm-devel@redhat.com>, <rajur
 @chelsio
 .com>, <davem@davemloft.net>, <kuba@kernel.org>, <peppe.cavallaro@st.com>, <alexandre.torgue@st.com>, <joabreu@synopsys.com>, <mcoquelin.stm32@gmail.com>, <malattia@linux.it>, <hdegoede@redhat.com>, <mgross@linux.intel.com>, <intel-linux-scu@intel.com>, <artur.paszkiewicz@intel.com>, <jejb@linux.ibm.com>, <martin.petersen@oracle.com>, <sakari.ailus@linux.intel.com>, <clm@fb.com>, <josef@toxicpanda.com>, <dsterba@suse.com>, <xiang@kernel.org>, <chao@kernel.org>, <jack@suse.com>, <tytso@mit.edu>, <adilger.kernel@dilger.ca>, <dushistov@mail.ru>, <luc.vanoostenryck@gmail.com>, <rostedt@goodmis.org>, <pmladek@suse.com>, <sergey.senozhatsky@gmail.com>, <andriy.shevchenko@linux.intel.com>, <linux@rasmusvillemoes.dk>, <minchan@kernel.org>, <ngupta@vflare.org>, <akpm@linux-foundation.org>, <kuznet@ms2.inr.ac.ru>, <yoshfuji@linux-ipv6.org>, <pablo@netfilter.org>, <kadlec@netfilter.org>, <fw@strlen.de>, <jmaloy@redhat.com>, <ying.xue@windriver.com>, <willy@infradead.org>, <farbere@amaz
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  <sashal@kernel.org>, <ruanjinjie@huawei.com>, <David.Laight@ACULAB.COM>, <herve.codina@bootlin.com>, <Jason@zx2c4.com>, <keescook@chromium.org>, <kbusch@kernel.org>, <nathan@kernel.org>, <bvanassche@acm.org>, <ndesaulniers@google.com>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <linux-um@lists.infradead.org>, <linux-edac@vger.kernel.org>, <amd-gfx@lists.freedesktop.org>, <dri-devel@lists.freedesktop.org>, <linux-arm-msm@vger.kernel.org>, <freedreno@lists.freedesktop.org>, <linux-hwmon@vger.kernel.org>, <linux-input@vger.kernel.org>, <linux-media@vger.kernel.org>, <netdev@vger.kernel.org>, <linux-stm32@st-md-mailman.stormreply.com>, <platform-driver-x86@vger.kernel.org>, <linux-scsi@vger.kernel.org>, <linux-staging@lists.linux.dev>, <linux-btrfs@vger.kernel.org>, <linux-erofs@lists.ozlabs.org>, <linux-ext4@vger.kernel.org>, <linux-sparse@vger.kernel.org>, <linux-mm@kvack.org>, <netfilter-devel@vger.kernel.org>, <coreteam@netfilter.org>, <tipc-dis
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Cc: Andy Shevchenko <andy.shevchenko@gmail.com>, Christophe Leroy <christophe.leroy@csgroup.eu>
Message-ID: <20251017090519.46992-7-farbere@amazon.com>

From: Herve Codina <herve.codina@bootlin.com>

[ Upstream commit c952c748c7a983a8bda9112984e6f2c1f6e441a5 ]

Introduce min_array() (resp max_array()) in order to get the
minimal (resp maximum) of values present in an array.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20230623085830.749991-8-herve.codina@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/minmax.h |   64 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -151,6 +151,70 @@
  */
 #define max_t(type, x, y)	__careful_cmp((type)(x), (type)(y), >)
 
+/*
+ * Remove a const qualifier from integer types
+ * _Generic(foo, type-name: association, ..., default: association) performs a
+ * comparison against the foo type (not the qualified type).
+ * Do not use the const keyword in the type-name as it will not match the
+ * unqualified type of foo.
+ */
+#define __unconst_integer_type_cases(type)	\
+	unsigned type:  (unsigned type)0,	\
+	signed type:    (signed type)0
+
+#define __unconst_integer_typeof(x) typeof(			\
+	_Generic((x),						\
+		char: (char)0,					\
+		__unconst_integer_type_cases(char),		\
+		__unconst_integer_type_cases(short),		\
+		__unconst_integer_type_cases(int),		\
+		__unconst_integer_type_cases(long),		\
+		__unconst_integer_type_cases(long long),	\
+		default: (x)))
+
+/*
+ * Do not check the array parameter using __must_be_array().
+ * In the following legit use-case where the "array" passed is a simple pointer,
+ * __must_be_array() will return a failure.
+ * --- 8< ---
+ * int *buff
+ * ...
+ * min = min_array(buff, nb_items);
+ * --- 8< ---
+ *
+ * The first typeof(&(array)[0]) is needed in order to support arrays of both
+ * 'int *buff' and 'int buff[N]' types.
+ *
+ * The array can be an array of const items.
+ * typeof() keeps the const qualifier. Use __unconst_integer_typeof() in order
+ * to discard the const qualifier for the __element variable.
+ */
+#define __minmax_array(op, array, len) ({				\
+	typeof(&(array)[0]) __array = (array);				\
+	typeof(len) __len = (len);					\
+	__unconst_integer_typeof(__array[0]) __element = __array[--__len]; \
+	while (__len--)							\
+		__element = op(__element, __array[__len]);		\
+	__element; })
+
+/**
+ * min_array - return minimum of values present in an array
+ * @array: array
+ * @len: array length
+ *
+ * Note that @len must not be zero (empty array).
+ */
+#define min_array(array, len) __minmax_array(min, array, len)
+
+/**
+ * max_array - return maximum of values present in an array
+ * @array: array
+ * @len: array length
+ *
+ * Note that @len must not be zero (empty array).
+ */
+#define max_array(array, len) __minmax_array(max, array, len)
+
 /**
  * clamp_t - return a value clamped to a given range using a given type
  * @type: the type of variable to use


Patches currently in stable-queue which might be from farbere@amazon.com are

queue-5.10/minmax-allow-comparisons-of-int-against-unsigned-char-short.patch
queue-5.10/minmax-add-a-few-more-min_t-max_t-users.patch
queue-5.10/minmax-improve-macro-expansion-and-type-checking.patch
queue-5.10/minmax-fix-indentation-of-__cmp_once-and-__clamp_once.patch
queue-5.10/minmax.h-simplify-the-variants-of-clamp.patch
queue-5.10/minmax-add-in_range-macro.patch
queue-5.10/minmax.h-move-all-the-clamp-definitions-after-the-min-max-ones.patch
queue-5.10/minmax-allow-min-max-clamp-if-the-arguments-have-the-same-signedness.patch
queue-5.10/minmax-don-t-use-max-in-situations-that-want-a-c-constant-expression.patch
queue-5.10/minmax.h-remove-some-defines-that-are-only-expanded-once.patch
queue-5.10/minmax.h-use-build_bug_on_msg-for-the-lo-hi-test-in-clamp.patch
queue-5.10/minmax-simplify-min-max-clamp-implementation.patch
queue-5.10/minmax-deduplicate-__unconst_integer_typeof.patch
queue-5.10/minmax-simplify-and-clarify-min_t-max_t-implementation.patch
queue-5.10/minmax.h-add-whitespace-around-operators-and-after-commas.patch
queue-5.10/minmax-sanity-check-constant-bounds-when-clamping.patch
queue-5.10/minmax-avoid-overly-complicated-constant-expressions-in-vm-code.patch
queue-5.10/minmax-make-generic-min-and-max-macros-available-everywhere.patch
queue-5.10/minmax-fix-up-min3-and-max3-too.patch
queue-5.10/minmax.h-reduce-the-define-expansion-of-min-max-and-clamp.patch
queue-5.10/minmax-fix-header-inclusions.patch
queue-5.10/minmax-introduce-min-max-_array.patch
queue-5.10/btrfs-remove-duplicated-in_range-macro.patch
queue-5.10/overflow-tracing-define-the-is_signed_type-macro-once.patch
queue-5.10/minmax-relax-check-to-allow-comparison-between-unsigned-arguments-and-signed-constants.patch
queue-5.10/minmax-clamp-more-efficiently-by-avoiding-extra-comparison.patch
queue-5.10/minmax.h-update-some-comments.patch