[PATCH RFC 17/35] mm/gup: drop nth_page() usage within folio when recording subpages
From: David Hildenbrand <hidden>
Date: 2025-08-21 20:07:57
Also in:
dri-devel, intel-gfx, io-uring, kvm, linux-arm-kernel, linux-crypto, linux-ide, linux-iommu, linux-kselftest, linux-mips, linux-mm, linux-mmc, linux-riscv, linux-s390, linux-scsi, lkml, virtualization
Subsystem:
memory management, memory management - gup (get user pages), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
nth_page() is no longer required when iterating over pages within a single folio, so let's just drop it when recording subpages. Signed-off-by: David Hildenbrand <redacted> --- mm/gup.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index b2a78f0291273..f017ff6d7d61a 100644
--- a/mm/gup.c
+++ b/mm/gup.c@@ -491,9 +491,9 @@ static int record_subpages(struct page *page, unsigned long sz, struct page *start_page; int nr; - start_page = nth_page(page, (addr & (sz - 1)) >> PAGE_SHIFT); + start_page = page + ((addr & (sz - 1)) >> PAGE_SHIFT); for (nr = 0; addr != end; nr++, addr += PAGE_SIZE) - pages[nr] = nth_page(start_page, nr); + pages[nr] = start_page + nr; return nr; }
@@ -1512,7 +1512,7 @@ static long __get_user_pages(struct mm_struct *mm, } for (j = 0; j < page_increm; j++) { - subpage = nth_page(page, j); + subpage = page + j; pages[i + j] = subpage; flush_anon_page(vma, subpage, start + j * PAGE_SIZE); flush_dcache_page(subpage);
--
2.50.1