From: David Hildenbrand <david@redhat.com>
Date: Mon, 1 Sep 2025 15:03:39 +0000 (+0200)
Subject: mm/gup: drop nth_page() usage within folio when recording subpages
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7a7c4dd8211474e63d7fafd3445475f55003bc9e;p=users%2Fjedix%2Flinux-maple.git

mm/gup: drop nth_page() usage within folio when recording subpages

nth_page() is no longer required when iterating over pages within a single
folio, so let's just drop it when recording subpages.

Link: https://lkml.kernel.org/r/20250901150359.867252-19-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/gup.c b/mm/gup.c
index ed02d65f9c72..e1bd2b2e9145 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -488,12 +488,11 @@ static int record_subpages(struct page *page, unsigned long sz,
 			   unsigned long addr, unsigned long end,
 			   struct page **pages)
 {
-	struct page *start_page;
 	int nr;
 
-	start_page = nth_page(page, (addr & (sz - 1)) >> PAGE_SHIFT);
+	page += (addr & (sz - 1)) >> PAGE_SHIFT;
 	for (nr = 0; addr != end; nr++, addr += PAGE_SIZE)
-		pages[nr] = nth_page(start_page, nr);
+		pages[nr] = page++;
 
 	return nr;
 }
@@ -1512,7 +1511,7 @@ next_page:
 			}
 
 			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);