Merge tag 'mm-stable-2025-06-01-14-06' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more MM updates from Andrew Morton:

 - "zram: support algorithm-specific parameters" from Sergey Senozhatsky
   adds infrastructure for passing algorithm-specific parameters into
   zram. A single parameter `winbits' is implemented at this time.

 - "memcg: nmi-safe kmem charging" from Shakeel Butt makes memcg
   charging nmi-safe, which is required by BFP, which can operate in NMI
   context.

 - "Some random fixes and cleanup to shmem" from Kemeng Shi implements
   small fixes and cleanups in the shmem code.

 - "Skip mm selftests instead when kernel features are not present" from
   Zi Yan fixes some issues in the MM selftest code.

 - "mm/damon: build-enable essential DAMON components by default" from
   SeongJae Park reworks DAMON Kconfig to make it easier to enable
   CONFIG_DAMON.

 - "sched/numa: add statistics of numa balance task migration" from Libo
   Chen adds more info into sysfs and procfs files to improve visibility
   into the NUMA balancer's task migration activity.

 - "selftests/mm: cow and gup_longterm cleanups" from Mark Brown
   provides various updates to some of the MM selftests to make them
   play better with the overall containing framework.

* tag 'mm-stable-2025-06-01-14-06' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (43 commits)
  mm/khugepaged: clean up refcount check using folio_expected_ref_count()
  selftests/mm: fix test result reporting in gup_longterm
  selftests/mm: report unique test names for each cow test
  selftests/mm: add helper for logging test start and results
  selftests/mm: use standard ksft_finished() in cow and gup_longterm
  selftests/damon/_damon_sysfs: skip testcases if CONFIG_DAMON_SYSFS is disabled
  sched/numa: add statistics of numa balance task
  sched/numa: fix task swap by skipping kernel threads
  tools/testing: check correct variable in open_procmap()
  tools/testing/vma: add missing function stub
  mm/gup: update comment explaining why gup_fast() disables IRQs
  selftests/mm: two fixes for the pfnmap test
  mm/khugepaged: fix race with folio split/free using temporary reference
  mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order
  mmu_notifiers: remove leftover stub macros
  selftests/mm: deduplicate test names in madv_populate
  kcov: rust: add flags for KCOV with Rust
  mm: rust: make CONFIG_MMU ifdefs more narrow
  mmu_gather: move tlb flush for VM_PFNMAP/VM_MIXEDMAP vmas into free_pgtables()
  mm/damon/Kconfig: enable CONFIG_DAMON by default
  ...

1 files changed, 13 insertions, 16 deletions

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index d9e19fb2dcf3..969d4ad510df 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -457,38 +457,35 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
 }
 EXPORT_SYMBOL(iov_iter_zero);
 
-size_t copy_page_from_iter_atomic(struct page *page, size_t offset,
+size_t copy_folio_from_iter_atomic(struct folio *folio, size_t offset,
 		size_t bytes, struct iov_iter *i)
 {
 	size_t n, copied = 0;
-	bool uses_kmap = IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) ||
-			 PageHighMem(page);
 
-	if (!page_copy_sane(page, offset, bytes))
+	if (!page_copy_sane(&folio->page, offset, bytes))
 		return 0;
 	if (WARN_ON_ONCE(!i->data_source))
 		return 0;
 
 	do {
-		char *p;
+		char *to = kmap_local_folio(folio, offset);
 
 		n = bytes - copied;
-		if (uses_kmap) {
-			page += offset / PAGE_SIZE;
-			offset %= PAGE_SIZE;
-			n = min_t(size_t, n, PAGE_SIZE - offset);
-		}
-
-		p = kmap_atomic(page) + offset;
-		n = __copy_from_iter(p, n, i);
-		kunmap_atomic(p);
+		if (folio_test_partial_kmap(folio) &&
+		    n > PAGE_SIZE - offset_in_page(offset))
+			n = PAGE_SIZE - offset_in_page(offset);
+
+		pagefault_disable();
+		n = __copy_from_iter(to, n, i);
+		pagefault_enable();
+		kunmap_local(to);
 		copied += n;
 		offset += n;
-	} while (uses_kmap && copied != bytes && n > 0);
+	} while (copied != bytes && n > 0);
 
 	return copied;
 }
-EXPORT_SYMBOL(copy_page_from_iter_atomic);
+EXPORT_SYMBOL(copy_folio_from_iter_atomic);
 
 static void iov_iter_bvec_advance(struct iov_iter *i, size_t size)
 {