From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 E893A244687; Wed, 23 Sep 2026 14:54:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790175249; cv=none; b=TsDtt6dul2q3wk9Ae0q2fEF/18xjbivaSfOnBtwkDwOL6i02RGxRfn5aQBcEkLVLCqNSzLn9iJ6gR2Hi8riuXLc4OVJutSxeE7G7iva3EhjSZBffIwFGD8CFy8BlkzspZfeuaPOTLGP49CZeAvZe34l3soJRdyjRQlMCtEUSCiM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790175249; c=relaxed/simple; bh=v7ob1bXtGQ8Me5gB2x20UlY+q3jR8b40QHcjOIp+a7I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SwB4F1QNnNKCQayVeRyT35SLcVymZ0FBkuLT7GrWJZmyb88+EEuywbscXjvbNwjsIFBDxE7XJ1lNRZCZevbSRshRaHZ9g3NoGymPRwwElrMSDfZLQKjR+wuLl6Y/6e4c+Cvv2lDMlJzVZqRqn/q2nxL0MEISIq789mxa1l12Iec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pxwIW1Qo; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pxwIW1Qo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 26BD61F000FF; Wed, 23 Sep 2026 14:54:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790175247; bh=HKVNHQgAnbFmepZfFKyijIUrGO7ahKGE79KRBjlURco=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=pxwIW1QoV7a61OrYGLdUdr8TbCHSNYffYL6FDkkzpdZQTCuRtSuGkxTRelYdXp7iY E3PoSNa0aAc5DptpBCRE7dyDicRDxHQ86Z7nkg7pLAytMvOcO4TzrAfnEr+1fhrTaJ SqJEMO3sc/qaOguGNF9M58ZzcJnggC3RC79lbFgg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "David Hildenbrand (Arm)" , "Lorenzo Stoakes (Oracle)" , "Mike Rapoport (Microsoft)" , Dan Williams , "Christophe Leroy (CS GROUP)" , Jann Horn , Liam Howlett , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Muchun Song , Nicholas Piggin , Oscar Salvador , Paolo Bonzini , Pedro Falcato , Suren Baghdasaryan , Andrew Morton , Sasha Levin Subject: [PATCH 6.18 368/398] mm: move vma_kernel_pagesize() from hugetlb to mm.h Date: Wed, 23 Sep 2026 16:07:22 +0200 Message-ID: <20260923140652.982079812@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140643.441954610@linuxfoundation.org> References: <20260923140643.441954610@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: "David Hildenbrand (Arm)" [ Upstream commit 341ffe82a7a3a1e0756b58999405b6df0c2b3e8d ] Patch series "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c", v2. Looking into vma_(kernel|mmu)_pagesize(), I realized that there is one scenario where DAX would not do the right thing when the kernel is not compiled with hugetlb support. Without hugetlb support, vma_(kernel|mmu)_pagesize() will always return PAGE_SIZE instead of using the ->pagesize() result provided by dax-device code. Fix that by moving vma_kernel_pagesize() to core MM code, where it belongs. I don't think this is stable material, but am not 100% sure. Also, move vma_mmu_pagesize() while at it. Remove the unnecessary hugetlb.h inclusion from KVM code. This patch (of 4): In the past, only hugetlb had special "vma_kernel_pagesize()" requirements, so it provided its own implementation. In commit 05ea88608d4e ("mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct") we generalized that approach by providing a vm_ops->pagesize() callback to be used by device-dax. Once device-dax started using that callback in commit c1d53b92b95c ("device-dax: implement ->pagesize() for smaps to report MMUPageSize") it was missed that CONFIG_DEV_DAX does not depend on hugetlb support. So building a kernel with CONFIG_DEV_DAX but without CONFIG_HUGETLBFS would not pick up that value. Fix it by moving vma_kernel_pagesize() to mm.h, providing only a single implementation. While at it, improve the kerneldoc a bit. Ideally, we'd move vma_mmu_pagesize() as well to the header. However, its __weak symbol might be overwritten by a PPC variant in hugetlb code. So let's leave it in there for now, as it really only matters for some hugetlb oddities. This was found by code inspection. Link: https://lkml.kernel.org/r/20260309151901.123947-1-david@kernel.org Link: https://lkml.kernel.org/r/20260309151901.123947-2-david@kernel.org Fixes: c1d53b92b95c ("device-dax: implement ->pagesize() for smaps to report MMUPageSize") Signed-off-by: David Hildenbrand (Arm) Reviewed-by: Lorenzo Stoakes (Oracle) Acked-by: Mike Rapoport (Microsoft) Cc: Dan Williams Cc: "Christophe Leroy (CS GROUP)" Cc: Jann Horn Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Muchun Song Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Paolo Bonzini Cc: Pedro Falcato Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton Stable-dep-of: e384abeb559d ("mm/huge_memory: bypass THP tuneables for huge pfnmap mappings") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/linux/hugetlb.h | 7 ------- include/linux/mm.h | 20 ++++++++++++++++++++ mm/hugetlb.c | 17 ----------------- 3 files changed, 20 insertions(+), 24 deletions(-) --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -767,8 +767,6 @@ static inline unsigned long huge_page_si return (unsigned long)PAGE_SIZE << h->order; } -extern unsigned long vma_kernel_pagesize(struct vm_area_struct *vma); - extern unsigned long vma_mmu_pagesize(struct vm_area_struct *vma); static inline unsigned long huge_page_mask(struct hstate *h) @@ -1184,11 +1182,6 @@ static inline unsigned long huge_page_ma return PAGE_MASK; } -static inline unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) -{ - return PAGE_SIZE; -} - static inline unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) { return PAGE_SIZE; --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1020,6 +1020,26 @@ static inline bool vma_is_shared_maywrit return is_shared_maywrite(vma->vm_flags); } +/** + * vma_kernel_pagesize - Default page size granularity for this VMA. + * @vma: The user mapping. + * + * The kernel page size specifies in which granularity VMA modifications + * can be performed. Folios in this VMA will be aligned to, and at least + * the size of the number of bytes returned by this function. + * + * The default kernel page size is not affected by Transparent Huge Pages + * being in effect. + * + * Return: The default page size granularity for this VMA. + */ +static inline unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) +{ + if (unlikely(vma->vm_ops && vma->vm_ops->pagesize)) + return vma->vm_ops->pagesize(vma); + return PAGE_SIZE; +} + static inline struct vm_area_struct *vma_find(struct vma_iterator *vmi, unsigned long max) { --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1027,23 +1027,6 @@ static pgoff_t vma_hugecache_offset(stru (vma->vm_pgoff >> huge_page_order(h)); } -/** - * vma_kernel_pagesize - Page size granularity for this VMA. - * @vma: The user mapping. - * - * Folios in this VMA will be aligned to, and at least the size of the - * number of bytes returned by this function. - * - * Return: The default size of the folios allocated when backing a VMA. - */ -unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) -{ - if (vma->vm_ops && vma->vm_ops->pagesize) - return vma->vm_ops->pagesize(vma); - return PAGE_SIZE; -} -EXPORT_SYMBOL_GPL(vma_kernel_pagesize); - /* * Return the page size being used by the MMU to back a VMA. In the majority * of cases, the page size used by the kernel matches the MMU size. On