In preparation for wp support mthp, add offset to start copy for
copy_user_large_folio() function.

Signed-off-by: Vernon Yang <vernon2gm@gmail.com>
---
 include/linux/mm.h |  1 +
 mm/hugetlb.c       |  6 +++---
 mm/memory.c        | 11 ++++++++---
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80c6673f419e..e178fb1049f7 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4006,6 +4006,7 @@ enum mf_action_page_type {
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
 void folio_zero_user(struct folio *folio, unsigned long addr_hint);
 int copy_user_large_folio(struct folio *dst, struct folio *src,
+			  unsigned int offset,
 			  unsigned long addr_hint,
 			  struct vm_area_struct *vma);
 long copy_folio_from_user(struct folio *dst_folio,
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a0d285d20992..91e1ec73f092 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5682,7 +5682,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 					break;
 				}
 				ret = copy_user_large_folio(new_folio, pte_folio,
-							    addr, dst_vma);
+							    0, addr, dst_vma);
 				folio_put(pte_folio);
 				if (ret) {
 					folio_put(new_folio);
@@ -6277,7 +6277,7 @@ static vm_fault_t hugetlb_wp(struct folio *pagecache_folio,
 	if (unlikely(ret))
 		goto out_release_all;
 
-	if (copy_user_large_folio(new_folio, old_folio, vmf->real_address, vma)) {
+	if (copy_user_large_folio(new_folio, old_folio, 0, vmf->real_address, vma)) {
 		ret = VM_FAULT_HWPOISON_LARGE | VM_FAULT_SET_HINDEX(hstate_index(h));
 		goto out_release_all;
 	}
@@ -6992,7 +6992,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 			*foliop = NULL;
 			goto out;
 		}
-		ret = copy_user_large_folio(folio, *foliop, dst_addr, dst_vma);
+		ret = copy_user_large_folio(folio, *foliop, 0, dst_addr, dst_vma);
 		folio_put(*foliop);
 		*foliop = NULL;
 		if (ret) {
diff --git a/mm/memory.c b/mm/memory.c
index 7b8c7d0f9ff4..3451e6e5aabd 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -7071,6 +7071,7 @@ void folio_zero_user(struct folio *folio, unsigned long addr_hint)
 }
 
 static int copy_user_gigantic_page(struct folio *dst, struct folio *src,
+				   unsigned int offset,
 				   unsigned long addr_hint,
 				   struct vm_area_struct *vma,
 				   unsigned int nr_pages)
@@ -7082,7 +7083,7 @@ static int copy_user_gigantic_page(struct folio *dst, struct folio *src,
 
 	for (i = 0; i < nr_pages; i++) {
 		dst_page = folio_page(dst, i);
-		src_page = folio_page(src, i);
+		src_page = folio_page(src, offset + i);
 
 		cond_resched();
 		if (copy_mc_user_highpage(dst_page, src_page,
@@ -7095,6 +7096,7 @@ static int copy_user_gigantic_page(struct folio *dst, struct folio *src,
 struct copy_subpage_arg {
 	struct folio *dst;
 	struct folio *src;
+	unsigned int offset;
 	struct vm_area_struct *vma;
 };
 
@@ -7102,7 +7104,7 @@ static int copy_subpage(unsigned long addr, int idx, void *arg)
 {
 	struct copy_subpage_arg *copy_arg = arg;
 	struct page *dst = folio_page(copy_arg->dst, idx);
-	struct page *src = folio_page(copy_arg->src, idx);
+	struct page *src = folio_page(copy_arg->src, copy_arg->offset + idx);
 
 	if (copy_mc_user_highpage(dst, src, addr, copy_arg->vma))
 		return -EHWPOISON;
@@ -7110,17 +7112,20 @@ static int copy_subpage(unsigned long addr, int idx, void *arg)
 }
 
 int copy_user_large_folio(struct folio *dst, struct folio *src,
+			  unsigned int offset,
 			  unsigned long addr_hint, struct vm_area_struct *vma)
 {
 	unsigned int nr_pages = folio_nr_pages(dst);
 	struct copy_subpage_arg arg = {
 		.dst = dst,
 		.src = src,
+		.offset = offset,
 		.vma = vma,
 	};
 
 	if (unlikely(nr_pages > MAX_ORDER_NR_PAGES))
-		return copy_user_gigantic_page(dst, src, addr_hint, vma, nr_pages);
+		return copy_user_gigantic_page(dst, src, offset, addr_hint,
+					       vma, nr_pages);
 
 	return process_huge_page(addr_hint, nr_pages, copy_subpage, &arg);
 }
-- 
2.50.1