From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 3CA694DA53B; Thu, 9 Jul 2026 17:58:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783619885; cv=none; b=S9i542iPakdTMh5YTHyoA6/5yZyXEhmImNwLP3kmzuWOirlhYcW7tlNlGMP+oEDTOocAKaGCdZ6FXyx3QUTr21QMXYTi+/oRLBoiTNM5kIxt6uf6+TkmCBtLSJutDe2Rp1uY4JQ6ODUkE6jI/wHrgO3roWmNwlhe/W4c8E5YC6U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783619885; c=relaxed/simple; bh=ueCfC8mj9W6I1SlYqEpl674vMNV2wFKokvVZLAzEXzA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Zr/BJlkbfc31imioGeBGIU4shkOYceQysX/Vv51Ck3OoCxanRTkNf7FqbjBcsqc/GQCnonJFvw0as4s4Ji0q4NbFb1zmSx617DN0WsqovxeUs9aIP7MWHZ0pHz0oxNUaWFtnqvyTYVSJ7d1XgKzi0NuU06UMKxHhZKiMgiyPvKw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=QinGRakq; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="QinGRakq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1783619885; x=1815155885; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=ueCfC8mj9W6I1SlYqEpl674vMNV2wFKokvVZLAzEXzA=; b=QinGRakq01yGwXdvDvTquHr/s0RRan5Ir9XySXk02l8qZeAiKN9413ae 3MtNp0rnXpHM3kzqarMKgLcB7pM6Fe6tdspo3gIerElyAEREkn6zX3FPt aERtWyPEE0DecN+W6ea/LB56siGEjTzLIvcyYC2aeDDGfiv2tsdgT5cBO /7Tp6HlwCQ0U/R7isW3ZiZmG3Tbm5M0XtH39PqZ70wgezHqv3o1bEXq// gJR7XHW5i7h4esRokBI7hasKC5zaFsrHoo9rPRqBeCKL0tDmXrFsmAKYr F2bMhE5zt8t+gYsqiJjWjNryf+dCM6HiGZNQ1Gz7rsPN9TEVTvYQJ0J7m g==; X-CSE-ConnectionGUID: Mc+SeyOfQeefoWRyQ4oofA== X-CSE-MsgGUID: woQ/Rz1mTouS+5D0fgahyg== X-IronPort-AV: E=McAfee;i="6800,10657,11841"; a="88139583" X-IronPort-AV: E=Sophos;i="6.25,154,1779174000"; d="scan'208";a="88139583" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2026 10:58:04 -0700 X-CSE-ConnectionGUID: hf/hEBL1SMaZOpk5XqzpzA== X-CSE-MsgGUID: mMZej/BNT82mbag9beBfMw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,154,1779174000"; d="scan'208";a="252920685" Received: from bradocaj-mobl.ger.corp.intel.com (HELO [10.125.111.142]) ([10.125.111.142]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2026 10:58:02 -0700 Message-ID: Date: Thu, 9 Jul 2026 10:58:00 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 01/10] mm/memory: add memory_block_aligned_range() helper To: Gregory Price , linux-mm@kvack.org Cc: nvdimm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, driver-core@lists.linux.dev, linux-kselftest@vger.kernel.org, kernel-team@meta.com, david@kernel.org, osalvador@suse.de, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, djbw@kernel.org, vishal.l.verma@intel.com, alison.schofield@intel.com, akpm@linux-foundation.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, iweiny@kernel.org, Smita.KoralahalliChannabasappa@amd.com, apopple@nvidia.com References: <20260630211842.2252800-1-gourry@gourry.net> <20260630211842.2252800-2-gourry@gourry.net> Content-Language: en-US From: Dave Jiang In-Reply-To: <20260630211842.2252800-2-gourry@gourry.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/30/26 2:18 PM, Gregory Price wrote: > Memory hotplug operations require ranges aligned to memory block > boundaries. This is a generic operation for hotplug. > > Add memory_block_aligned_range() as a common helper in > that aligns the start address up and end address down to memory block > boundaries. Guard against end underflow when the range falls below the > first memory block boundary, returning an empty range instead. > > Update dax/kmem to use this helper. > > Signed-off-by: Gregory Price > Acked-by: David Hildenbrand (Arm) Reviewed-by: Dave Jiang > --- > drivers/dax/kmem.c | 4 +--- > include/linux/memory.h | 27 +++++++++++++++++++++++++++ > 2 files changed, 28 insertions(+), 3 deletions(-) > > diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c > index a18e2b968e4d..592171ec10f4 100644 > --- a/drivers/dax/kmem.c > +++ b/drivers/dax/kmem.c > @@ -33,9 +33,7 @@ static int dax_kmem_range(struct dev_dax *dev_dax, int i, struct range *r) > struct dev_dax_range *dax_range = &dev_dax->ranges[i]; > struct range *range = &dax_range->range; > > - /* memory-block align the hotplug range */ > - r->start = ALIGN(range->start, memory_block_size_bytes()); > - r->end = ALIGN_DOWN(range->end + 1, memory_block_size_bytes()) - 1; > + *r = memory_block_aligned_range(range); > if (r->start >= r->end) { > r->start = range->start; > r->end = range->end; > diff --git a/include/linux/memory.h b/include/linux/memory.h > index 463dc02f6cff..1783299073e4 100644 > --- a/include/linux/memory.h > +++ b/include/linux/memory.h > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include > > #define MIN_MEMORY_BLOCK_SIZE (1UL << SECTION_SIZE_BITS) > > @@ -100,6 +101,32 @@ int arch_get_memory_phys_device(unsigned long start_pfn); > unsigned long memory_block_size_bytes(void); > int set_memory_block_size_order(unsigned int order); > > +/** > + * memory_block_aligned_range - align a physical address range to memory blocks > + * @range: the input range to align > + * > + * Aligns the start address up and the end address down to memory block > + * boundaries. This is required for memory hotplug operations which must > + * operate on memory-block aligned ranges. > + * > + * Returns the aligned range. Callers should check that the returned > + * range is valid (aligned.start < aligned.end) before using it. > + */ > +static inline struct range memory_block_aligned_range(const struct range *range) > +{ > + struct range aligned; > + > + aligned.start = ALIGN(range->start, memory_block_size_bytes()); > + aligned.end = ALIGN_DOWN(range->end + 1, memory_block_size_bytes()); > + /* No whole block fits (e.g. range below the first boundary): empty. */ > + if (aligned.end <= aligned.start) > + aligned.start = aligned.end; > + else > + aligned.end -= 1; > + > + return aligned; > +} > + > struct memory_notify { > unsigned long start_pfn; > unsigned long nr_pages;