linux-kernel - [PATCH RFC 17/35] mm/gup: drop nth_page() usage within folio when recording subpages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250821200701.1329277-18-david@redhat.com>
Date: Thu, 21 Aug 2025 22:06:43 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: David Hildenbrand <david@...hat.com>,
	Alexander Potapenko <glider@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Brendan Jackman <jackmanb@...gle.com>,
	Christoph Lameter <cl@...two.org>,
	Dennis Zhou <dennis@...nel.org>,
	Dmitry Vyukov <dvyukov@...gle.com>,
	dri-devel@...ts.freedesktop.org,
	intel-gfx@...ts.freedesktop.org,
	iommu@...ts.linux.dev,
	io-uring@...r.kernel.org,
	Jason Gunthorpe <jgg@...dia.com>,
	Jens Axboe <axboe@...nel.dk>,
	Johannes Weiner <hannes@...xchg.org>,
	John Hubbard <jhubbard@...dia.com>,
	kasan-dev@...glegroups.com,
	kvm@...r.kernel.org,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-arm-kernel@...s.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-crypto@...r.kernel.org,
	linux-ide@...r.kernel.org,
	linux-kselftest@...r.kernel.org,
	linux-mips@...r.kernel.org,
	linux-mmc@...r.kernel.org,
	linux-mm@...ck.org,
	linux-riscv@...ts.infradead.org,
	linux-s390@...r.kernel.org,
	linux-scsi@...r.kernel.org,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	Marco Elver <elver@...gle.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Michal Hocko <mhocko@...e.com>,
	Mike Rapoport <rppt@...nel.org>,
	Muchun Song <muchun.song@...ux.dev>,
	netdev@...r.kernel.org,
	Oscar Salvador <osalvador@...e.de>,
	Peter Xu <peterx@...hat.com>,
	Robin Murphy <robin.murphy@....com>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Tejun Heo <tj@...nel.org>,
	virtualization@...ts.linux.dev,
	Vlastimil Babka <vbabka@...e.cz>,
	wireguard@...ts.zx2c4.com,
	x86@...nel.org,
	Zi Yan <ziy@...dia.com>
Subject: [PATCH RFC 17/35] 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.

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 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