From: Rik van Riel To: linux-kernel@vger.kernel.org Cc: kernel-team@meta.com, Rik van Riel , Andrew Morton , David Hildenbrand , Jason Gunthorpe , John Hubbard , Peter Xu , linux-mm@kvack.org Subject: [RFC PATCH v3 1/8] mm/gup: break out gup_fill_pages() helper Date: Mon, 10 Aug 2026 22:51:50 -0400 [thread overview] Message-ID: <20260811025157.1632867-2-riel@surriel.com> (raw) In-Reply-To: <20260811025157.1632867-1-riel@surriel.com> __get_user_pages() fills pages[] and flushes each page's caches in an open-coded loop. Move it into a gup_fill_pages() helper, which the follow_page_mask() call chain can then use to fill its own pages[] slots. No functional changes intended. Suggested-by: David Hildenbrand Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Rik van Riel --- mm/gup.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 0692119b7904..7bb40be89529 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -633,6 +633,23 @@ static struct page *no_page_table(struct vm_area_struct *vma, return NULL; } +static void gup_fill_pages(struct vm_area_struct *vma, unsigned long address, + struct page *page, unsigned long nr, struct page **pages) +{ + unsigned long i; + + if (!pages) + return; + + for (i = 0; i < nr; i++) { + struct page *subpage = page + i; + + pages[i] = subpage; + flush_anon_page(vma, subpage, address + i * PAGE_SIZE); + flush_dcache_page(subpage); + } +} + #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, @@ -1461,9 +1478,6 @@ static long __get_user_pages(struct mm_struct *mm, page_increm = nr_pages; if (pages) { - struct page *subpage; - unsigned int j; - /* * This must be a large folio (and doesn't need to * be the whole folio; it can be part of it), do @@ -1493,12 +1507,7 @@ static long __get_user_pages(struct mm_struct *mm, } } - for (j = 0; j < page_increm; j++) { - subpage = page + j; - pages[i + j] = subpage; - flush_anon_page(vma, subpage, start + j * PAGE_SIZE); - flush_dcache_page(subpage); - } + gup_fill_pages(vma, start, page, page_increm, pages + i); } i += page_increm; -- 2.55.0