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 A3E28380FC6; Sun, 23 Aug 2026 12:17:57 +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=1787487478; cv=none; b=X+uQrsvCHSakkxQdQXdqUEmL0z5Yh8EK2Ft3bCKnKw9GqJHO0gdb849sFKQpR0HIjt3ni5ioA/FotxYqatszoDGEt3ObFafVlexnjPBvNcTa3ZvkhAf1POSr+AeUyV9bgra0Eza9waXK6ByUOV1mvR3aQlhz111LX8bk677ZHAU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787487478; c=relaxed/simple; bh=31qEUMxCD1kfVB9JiEfF3V96sT9VroYttG2bG4L6wiY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=YcWnXVv2GX7lQczgk4Pu7sCXCwVZ0J4L9zqtm8WRA3fSR+CvVuJlNY0GqzwTSuUCCEjG4rTr9pli1RahT+tn767oDpLWZ6kxqt2gxATCxxqp0KJ3GLPZQhlzlcNY7uX31MK7ynceo4vYka0+i4JSa7ylq1zXIxt3y5CblGJeHeQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JdB62QeL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JdB62QeL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F9721F00A3A; Sun, 23 Aug 2026 12:17:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787487477; bh=phtAfk9967tvw5jCZ8EwhMxuR9BV70DOT2vnREg6Av0=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=JdB62QeLHfrgk01rU7saumkTHude9O5ljmTk8ojegK2RGvEuN1X6v0+bfsUBT3oC8 BrrdKyH8U+RenOUG0fNyJGhL761oH3Uggo6pqg/KnEcJ8gvjVzWNkQd+eUxp3Cy4nK ppxrXNG7PBxHFWlT9GuW0UhWK/ezVtolSz/FTRGF7LcYtPJHhV8w4QvIyFiT59gttD FqaZ/wlxuzjVHlojywG4R7foLh5P3doLWKkw0bKIj+L4G6DeZX6+lX3GRS653oR5vz Kjhrj0tTRMDE2EJm5T0PvMXlQSrTWVyAkH+VBPOJmvZAcUq17e1hyIlMUAmNPEIf1f EGV0bagWOWW5A== From: "Mike Rapoport (Microsoft)" Date: Sun, 23 Aug 2026 15:17:38 +0300 Subject: [PATCH 1/6] mm/gup: move gup_can_follow_protnone() to gup.c Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260823-uffd-vm-flags-v1-v1-1-3086981b33cf@kernel.org> References: <20260823-uffd-vm-flags-v1-v1-0-3086981b33cf@kernel.org> In-Reply-To: <20260823-uffd-vm-flags-v1-v1-0-3086981b33cf@kernel.org> To: Andrew Morton , David Hildenbrand Cc: Baolin Wang , Barry Song , Dev Jain , Hugh Dickins , Jann Horn , Jason Gunthorpe , John Hubbard , Jonathan Corbet , Lance Yang , "Liam R. Howlett" , Lorenzo Stoakes , Masami Hiramatsu , Mathieu Desnoyers , Mike Rapoport , Michal Hocko , Muchun Song , Nico Pache , Oscar Salvador , Pedro Falcato , Peter Xu , Ryan Roberts , Shakeel Butt , Shuah Khan , Steven Rostedt , Suren Baghdasaryan , Usama Arif , Vlastimil Babka , Zi Yan , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org X-Mailer: b4 0.17-dev gup_can_follow_protnone() is defined in include/linux/mm.h but only used by mm/gup.c. First, there is no reason to have it in already gigantic header. Next, the upcoming refactoring of userfaultfd flags will make gup_can_follow_protnone() depend on userfaultfd_k.h which would cause a cyclic header dependency. Move gup_can_follow_protnone() to mm/gup.c. No functional change. Assisted-by: copilot:claude-opus-5 Signed-off-by: Mike Rapoport (Microsoft) --- include/linux/mm.h | 38 -------------------------------------- mm/gup.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+), 38 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0829e0d3b2d1..4daf9cd6ae8e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4860,44 +4860,6 @@ static inline int vm_fault_to_errno(vm_fault_t vm_fault, int foll_flags) return 0; } -/* - * Indicates whether GUP can follow a PROT_NONE mapped page, or whether - * a (NUMA hinting or userfaultfd RWP) fault is required. - */ -static inline bool gup_can_follow_protnone(const struct vm_area_struct *vma, - unsigned int flags) -{ - /* - * VM_UFFD_RWP uses protnone as an access-tracking marker, not for - * NUMA hinting. GUP must always take a fault so the access is - * delivered to userfaultfd, regardless of FOLL_HONOR_NUMA_FAULT. - * - * Only do so while the VMA is accessible. If it has been made - * inaccessible (e.g. mprotect(PROT_NONE)), fall through to the guard - * below: forcing a fault there would loop, as handle_mm_fault() makes - * no progress on protnone in an inaccessible VMA, and the access is - * denied regardless of RWP anyway. - */ - if (vma_test_single_mask(vma, VMA_UFFD_RWP) && vma_is_accessible(vma)) - return false; - - /* - * If callers don't want to honor NUMA hinting faults, no need to - * determine if we would actually have to trigger a NUMA hinting fault. - */ - if (!(flags & FOLL_HONOR_NUMA_FAULT)) - return true; - - /* - * NUMA hinting faults don't apply in inaccessible (PROT_NONE) VMAs. - * - * Requiring a fault here even for inaccessible VMAs would mean that - * FOLL_FORCE cannot make any progress, because handle_mm_fault() - * refuses to process NUMA hinting faults in inaccessible VMAs. - */ - return !vma_is_accessible(vma); -} - typedef int (*pte_fn_t)(pte_t *pte, unsigned long addr, void *data); extern int apply_to_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, pte_fn_t fn, void *data); diff --git a/mm/gup.c b/mm/gup.c index eb898ea1ee22..500e2aa99e48 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -633,6 +633,44 @@ static struct page *no_page_table(struct vm_area_struct *vma, return NULL; } +/* + * Indicates whether GUP can follow a PROT_NONE mapped page, or whether + * a (NUMA hinting or userfaultfd RWP) fault is required. + */ +static inline bool gup_can_follow_protnone(const struct vm_area_struct *vma, + unsigned int flags) +{ + /* + * VM_UFFD_RWP uses protnone as an access-tracking marker, not for + * NUMA hinting. GUP must always take a fault so the access is + * delivered to userfaultfd, regardless of FOLL_HONOR_NUMA_FAULT. + * + * Only do so while the VMA is accessible. If it has been made + * inaccessible (e.g. mprotect(PROT_NONE)), fall through to the guard + * below: forcing a fault there would loop, as handle_mm_fault() makes + * no progress on protnone in an inaccessible VMA, and the access is + * denied regardless of RWP anyway. + */ + if (vma_test_single_mask(vma, VMA_UFFD_RWP) && vma_is_accessible(vma)) + return false; + + /* + * If callers don't want to honor NUMA hinting faults, no need to + * determine if we would actually have to trigger a NUMA hinting fault. + */ + if (!(flags & FOLL_HONOR_NUMA_FAULT)) + return true; + + /* + * NUMA hinting faults don't apply in inaccessible (PROT_NONE) VMAs. + * + * Requiring a fault here even for inaccessible VMAs would mean that + * FOLL_FORCE cannot make any progress, because handle_mm_fault() + * refuses to process NUMA hinting faults in inaccessible VMAs. + */ + return !vma_is_accessible(vma); +} + #ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES /* FOLL_FORCE can write to even unwritable PUDs in COW mappings. */ static inline bool can_follow_write_pud(pud_t pud, struct page *page, -- 2.53.0