[PATCH 1/5] mm: remove find_subpage()

[Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>]

After commit a08c7193e4f1 ("mm/filemap: remove hugetlb special casing
in filemap.c"), the find_subpage() should remove hugetlb case as the
folio_file_page(), furthermore, we could convert to use folio_file_page()
to remove find_subpage().

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
 include/linux/pagemap.h | 13 -------------
 lib/iov_iter.c          | 24 +++++++++++++-----------
 2 files changed, 13 insertions(+), 24 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index d9c7edb6422b..68f59cd7637d 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -860,19 +860,6 @@ static inline bool folio_contains(struct folio *folio, pgoff_t index)
 	return index - folio_index(folio) < folio_nr_pages(folio);
 }
 
-/*
- * Given the page we found in the page cache, return the page corresponding
- * to this index in the file
- */
-static inline struct page *find_subpage(struct page *head, pgoff_t index)
-{
-	/* HugeTLBfs wants the head page regardless */
-	if (PageHuge(head))
-		return head;
-
-	return head + (index & (thp_nr_pages(head) - 1));
-}
-
 unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start,
 		pgoff_t end, struct folio_batch *fbatch);
 unsigned filemap_get_folios_contig(struct address_space *mapping,
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 4a6a9f419bd7..b0bb1e5ff331 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -891,21 +891,21 @@ static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa
 					  pgoff_t index, unsigned int nr_pages)
 {
 	XA_STATE(xas, xa, index);
-	struct page *page;
+	struct folio *folio;
 	unsigned int ret = 0;
 
 	rcu_read_lock();
-	for (page = xas_load(&xas); page; page = xas_next(&xas)) {
-		if (xas_retry(&xas, page))
+	for (folio = xas_load(&xas); folio; folio = xas_next(&xas)) {
+		if (xas_retry(&xas, folio))
 			continue;
 
 		/* Has the page moved or been split? */
-		if (unlikely(page != xas_reload(&xas))) {
+		if (unlikely(folio != xas_reload(&xas))) {
 			xas_reset(&xas);
 			continue;
 		}
 
-		pages[ret] = find_subpage(page, xas.xa_index);
+		pages[ret] = folio_file_page(folio, xas.xa_index);
 		get_page(pages[ret]);
 		if (++ret == nr_pages)
 			break;
@@ -1408,7 +1408,8 @@ static ssize_t iov_iter_extract_xarray_pages(struct iov_iter *i,
 					     iov_iter_extraction_t extraction_flags,
 					     size_t *offset0)
 {
-	struct page *page, **p;
+	struct page **p;
+	struct folio *folio;
 	unsigned int nr = 0, offset;
 	loff_t pos = i->xarray_start + i->iov_offset;
 	pgoff_t index = pos >> PAGE_SHIFT;
@@ -1420,20 +1421,21 @@ static ssize_t iov_iter_extract_xarray_pages(struct iov_iter *i,
 	maxpages = want_pages_array(pages, maxsize, offset, maxpages);
 	if (!maxpages)
 		return -ENOMEM;
+
 	p = *pages;
 
 	rcu_read_lock();
-	for (page = xas_load(&xas); page; page = xas_next(&xas)) {
-		if (xas_retry(&xas, page))
+	for (folio = xas_load(&xas); folio; folio = xas_next(&xas)) {
+		if (xas_retry(&xas, folio))
 			continue;
 
-		/* Has the page moved or been split? */
-		if (unlikely(page != xas_reload(&xas))) {
+		/* Has the folio moved or been split? */
+		if (unlikely(folio != xas_reload(&xas))) {
 			xas_reset(&xas);
 			continue;
 		}
 
-		p[nr++] = find_subpage(page, xas.xa_index);
+		p[nr++] = folio_file_page(folio, xas.xa_index);
 		if (nr == maxpages)
 			break;
 	}
-- 
2.27.0