From nobody Tue Feb 10 20:46:55 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2987F378D84; Mon, 9 Feb 2026 14:41:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770648099; cv=none; b=XRf8mOHw05ep3cftPsBCicOOMEq49/gfDu9ZO2+KWa6CTlj4r7B2fzgkPlNcxKNtSgb2BhMH6N/cGbQcqb4xOXLBK7lKUrH689o8LxgY+tra/HDoEBYY2uWLl4GkO+ce7Dc2He2HA+ntNk2ZOhtynmLFRefBUr5IV6IcfCqWyq4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770648099; c=relaxed/simple; bh=dIkOhzWY1xuDq5ewEz/XDIyATuNWlEhxlmAB0qWidMk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tX7BSJ3zt8+dRhTizHlAMXdwLDBvLFneV/0YSCPVwioCe+qef8LcWFJUMxkT2i4si3CRd6ZTs5AlwlkfnNRe0trH0H/rgWz0mOq3juCUlw/wFqtTJPKwn+CQEV0lshzIsGY26wKQcYpPzmrsqUXf9SbEzUT40oM3xGEIHUodJBM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IoiSaopD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IoiSaopD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D57DC116C6; Mon, 9 Feb 2026 14:41:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770648099; bh=dIkOhzWY1xuDq5ewEz/XDIyATuNWlEhxlmAB0qWidMk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IoiSaopDKfrfSZ7+rlBU8LjocFAFB8EJgAVaUZ/W+cBxwixSmGT1x/E8BIkMkjYP8 SzhptbW3ELmnRGgPqG0GC6S3X5YQ0NFlsp7/MwlGEwmonjJfjX36w6Zrid+02MdXYD aD13CKitrIkfiTc+tMswjO0GZ7FkCVjL6pg6DrkfeYhc3cdJymj5D1FMzCONDpjNPt CRTH696/5neg33D9wpXGgfmmIGyqUJnxX11v6uXDMEkOIdpDtKcYEzjVktAE2R8WVo jD3MvmL5DA+h5y6UTuTlFtK2d3SzKn7oXhmb/Hq02WBSEx3CHrl4//hhcmH0UMQ0G3 Ad/W6NbiDr+Ig== From: Mike Rapoport To: Andrew Morton Cc: Andreas Larsson , Borislav Petkov , Brian Cain , Catalin Marinas , "Christophe Leroy (CS GROUP)" , "David S. Miller" , Dave Hansen , David Hildenbrand , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , Helge Deller , Huacai Chen , Ingo Molnar , Johannes Berg , John Paul Adrian Glaubitz , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Magnus Lindholm , Matt Turner , Max Filippov , Michael Ellerman , Michal Hocko , Michal Simek , Mike Rapoport , Palmer Dabbelt , Richard Weinberger , Russell King , Stafford Horne , Suren Baghdasaryan , Thomas Gleixner , Vineet Gupta , Vlastimil Babka , Will Deacon , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org Subject: [PATCH v2 2/4] mm: rename my_zero_pfn() to zero_pfn() Date: Mon, 9 Feb 2026 16:40:55 +0200 Message-ID: <20260209144058.2092871-3-rppt@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260209144058.2092871-1-rppt@kernel.org> References: <20260209144058.2092871-1-rppt@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Mike Rapoport (Microsoft)" my_zero_pfn() is a silly name. Rename zero_pfn variable to zero_page_pfn and my_zero_pfn() function to zero_pfn(). While on it, move extern declarations of zero_page_pfn outside the functions that use it and add a comment about what ZERO_PAGE is. Signed-off-by: Mike Rapoport (Microsoft) --- arch/x86/kvm/mmu/spte.h | 2 +- fs/dax.c | 2 +- fs/proc/vmcore.c | 2 +- include/linux/pgtable.h | 25 +++++++++++++++++-------- mm/huge_memory.c | 2 +- mm/memory.c | 2 +- mm/migrate.c | 2 +- mm/mm_init.c | 10 +++++----- mm/userfaultfd.c | 4 ++-- 9 files changed, 30 insertions(+), 21 deletions(-) diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index 91ce29fd6f1b..8c0ffa2cded6 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -248,7 +248,7 @@ extern u64 __read_mostly shadow_nonpresent_or_rsvd_lowe= r_gfn_mask; =20 static inline hpa_t kvm_mmu_get_dummy_root(void) { - return my_zero_pfn(0) << PAGE_SHIFT; + return zero_pfn(0) << PAGE_SHIFT; } =20 static inline bool kvm_mmu_is_dummy_root(hpa_t shadow_page) diff --git a/fs/dax.c b/fs/dax.c index 289e6254aa30..b78cff9c91b3 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1360,7 +1360,7 @@ static vm_fault_t dax_load_hole(struct xa_state *xas,= struct vm_fault *vmf, { struct inode *inode =3D iter->inode; unsigned long vaddr =3D vmf->address; - unsigned long pfn =3D my_zero_pfn(vaddr); + unsigned long pfn =3D zero_pfn(vaddr); vm_fault_t ret; =20 *entry =3D dax_insert_entry(xas, vmf, iter, *entry, pfn, DAX_ZERO_PAGE); diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index f188bd900eb2..44d15436439f 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -525,7 +525,7 @@ static int remap_oldmem_pfn_checked(struct vm_area_stru= ct *vma, { unsigned long map_size; unsigned long pos_start, pos_end, pos; - unsigned long zeropage_pfn =3D my_zero_pfn(0); + unsigned long zeropage_pfn =3D zero_pfn(0); size_t len =3D 0; =20 pos_start =3D pfn; diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 08a88b0d56e5..a965e2f8b8de 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1882,27 +1882,36 @@ static inline void pfnmap_setup_cachemode_pfn(unsig= ned long pfn, pgprot_t *prot) pfnmap_setup_cachemode(pfn, PAGE_SIZE, prot); } =20 +/* + * ZERO_PAGE() is global shared page(s) that is always zero. It is used for + * zero-mapped memory areas, CoW etc. + * + * On architectures that __HAVE_COLOR_ZERO_PAGE there are several such pag= es + * for different ranges in the virtual address space. + * + * zero_page_pfn identifies the first (or the only) pfn for these pages. + */ +extern unsigned long zero_page_pfn; + #ifdef __HAVE_COLOR_ZERO_PAGE static inline int is_zero_pfn(unsigned long pfn) { - extern unsigned long zero_pfn; - unsigned long offset_from_zero_pfn =3D pfn - zero_pfn; + unsigned long offset_from_zero_pfn =3D pfn - zero_page_pfn; + return offset_from_zero_pfn <=3D (zero_page_mask >> PAGE_SHIFT); } =20 -#define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) +#define zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) =20 #else static inline int is_zero_pfn(unsigned long pfn) { - extern unsigned long zero_pfn; - return pfn =3D=3D zero_pfn; + return pfn =3D=3D zero_page_pfn; } =20 -static inline unsigned long my_zero_pfn(unsigned long addr) +static inline unsigned long zero_pfn(unsigned long addr) { - extern unsigned long zero_pfn; - return zero_pfn; + return zero_page_pfn; } #endif /* __HAVE_COLOR_ZERO_PAGE */ =20 diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 44ff8a648afd..bc15fd152526 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2968,7 +2968,7 @@ static void __split_huge_zero_page_pmd(struct vm_area= _struct *vma, for (i =3D 0, addr =3D haddr; i < HPAGE_PMD_NR; i++, addr +=3D PAGE_SIZE)= { pte_t entry; =20 - entry =3D pfn_pte(my_zero_pfn(addr), vma->vm_page_prot); + entry =3D pfn_pte(zero_pfn(addr), vma->vm_page_prot); entry =3D pte_mkspecial(entry); if (pmd_uffd_wp(old_pmd)) entry =3D pte_mkuffd_wp(entry); diff --git a/mm/memory.c b/mm/memory.c index 51d2018a387a..ae610afa9cea 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5165,7 +5165,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *= vmf) /* Use the zero-page for reads */ if (!(vmf->flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(vma->vm_mm)) { - entry =3D pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), + entry =3D pte_mkspecial(pfn_pte(zero_pfn(vmf->address), vma->vm_page_prot)); vmf->pte =3D pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); diff --git a/mm/migrate.c b/mm/migrate.c index 1bf2cf8c44dd..739c4e03769b 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -321,7 +321,7 @@ static bool try_to_map_unused_to_zeropage(struct page_v= ma_mapped_walk *pvmw, if (!pages_identical(page, ZERO_PAGE(0))) return false; =20 - newpte =3D pte_mkspecial(pfn_pte(my_zero_pfn(pvmw->address), + newpte =3D pte_mkspecial(pfn_pte(zero_pfn(pvmw->address), pvmw->vma->vm_page_prot)); =20 if (pte_swp_soft_dirty(old_pte)) diff --git a/mm/mm_init.c b/mm/mm_init.c index dcf9eff34f83..a0ca236eb4f5 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -53,8 +53,8 @@ EXPORT_SYMBOL(mem_map); void *high_memory; EXPORT_SYMBOL(high_memory); =20 -unsigned long zero_pfn __ro_after_init; -EXPORT_SYMBOL(zero_pfn); +unsigned long zero_page_pfn __ro_after_init; +EXPORT_SYMBOL(zero_page_pfn); =20 #ifdef CONFIG_DEBUG_MEMORY_INIT int __meminitdata mminit_loglevel; @@ -2670,12 +2670,12 @@ static void __init mem_init_print_info(void) ); } =20 -static int __init init_zero_pfn(void) +static int __init init_zero_page_pfn(void) { - zero_pfn =3D page_to_pfn(ZERO_PAGE(0)); + zero_page_pfn =3D page_to_pfn(ZERO_PAGE(0)); return 0; } -early_initcall(init_zero_pfn); +early_initcall(init_zero_page_pfn); =20 void __init __weak arch_mm_preinit(void) { diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 927086bb4a3c..e19872e51878 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -357,7 +357,7 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd, if (mm_forbids_zeropage(dst_vma->vm_mm)) return mfill_atomic_pte_zeroed_folio(dst_pmd, dst_vma, dst_addr); =20 - _dst_pte =3D pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), + _dst_pte =3D pte_mkspecial(pfn_pte(zero_pfn(dst_addr), dst_vma->vm_page_prot)); ret =3D -EAGAIN; dst_pte =3D pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl); @@ -1229,7 +1229,7 @@ static int move_zeropage_pte(struct mm_struct *mm, return -EAGAIN; } =20 - zero_pte =3D pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), + zero_pte =3D pte_mkspecial(pfn_pte(zero_pfn(dst_addr), dst_vma->vm_page_prot)); ptep_clear_flush(src_vma, src_addr, src_pte); set_pte_at(mm, dst_addr, dst_pte, zero_pte); --=20 2.51.0