[Patch v3] mm/huge_memory: simplify page tracking in remap_page() during folio split

[Wei Yang <richard.weiyang@gmail.com>]

After splitting a large folio, the resulting anonymous folios must be
remapped.

Currently, the code tracks progress by recording the number of processed
pages in an index variable (e.g., @i) and comparing it against the
total. This commit simplifies the logic by directly subtracting the
processed pages from the remaining count. This approach is more
straightforward and reduces the number of local variables.

Additionally, this commit renames the variable nr to nr_pages to improve
code readability and self-documentation.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>

---
v3: still use nr to count pages but subtract it directly
v2: move folio assignment in loop
---
 mm/huge_memory.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 40cf59301c21..d51aff0b7838 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3423,17 +3423,15 @@ bool unmap_huge_pmd_locked(struct vm_area_struct *vma, unsigned long addr,
 	return __discard_anon_folio_pmd_locked(vma, addr, pmdp, folio);
 }
 
-static void remap_page(struct folio *folio, unsigned long nr, int flags)
+static void remap_page(struct folio *folio, unsigned long nr_pages, int flags)
 {
-	int i = 0;
-
 	/* If unmap_folio() uses try_to_migrate() on file, remove this check */
 	if (!folio_test_anon(folio))
 		return;
 	for (;;) {
 		remove_migration_ptes(folio, folio, RMP_LOCKED | flags);
-		i += folio_nr_pages(folio);
-		if (i >= nr)
+		nr_pages -= folio_nr_pages(folio);
+		if (!nr_pages)
 			break;
 		folio = folio_next(folio);
 	}
-- 
2.34.1