1 files changed, 29 insertions, 19 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 657bcd887fdb..d62150418b91 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -177,7 +177,7 @@ static void filemap_unaccount_folio(struct address_space *mapping,
 				 * and we'd rather not leak it: if we're wrong,
 				 * another bad page check should catch it later.
 				 */
-				page_mapcount_reset(&folio->page);
+				atomic_set(&folio->_mapcount, -1);
 				folio_ref_sub(folio, mapcount);
 			}
 		}
@@ -1752,12 +1752,12 @@ pgoff_t page_cache_next_miss(struct address_space *mapping,
 	while (max_scan--) {
 		void *entry = xas_next(&xas);
 		if (!entry || xa_is_value(entry))
-			break;
+			return xas.xa_index;
 		if (xas.xa_index == 0)
-			break;
+			return 0;
 	}
 
-	return xas.xa_index;
+	return index + max_scan;
 }
 EXPORT_SYMBOL(page_cache_next_miss);
 
@@ -3982,21 +3982,24 @@ ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i)
 	loff_t pos = iocb->ki_pos;
 	struct address_space *mapping = file->f_mapping;
 	const struct address_space_operations *a_ops = mapping->a_ops;
+	size_t chunk = mapping_max_folio_size(mapping);
 	long status = 0;
 	ssize_t written = 0;
 
 	do {
 		struct page *page;
-		unsigned long offset;	/* Offset into pagecache page */
-		unsigned long bytes;	/* Bytes to write to page */
+		struct folio *folio;
+		size_t offset;		/* Offset into folio */
+		size_t bytes;		/* Bytes to write to folio */
 		size_t copied;		/* Bytes copied from user */
 		void *fsdata = NULL;
 
-		offset = (pos & (PAGE_SIZE - 1));
-		bytes = min_t(unsigned long, PAGE_SIZE - offset,
-						iov_iter_count(i));
+		bytes = iov_iter_count(i);
+retry:
+		offset = pos & (chunk - 1);
+		bytes = min(chunk - offset, bytes);
+		balance_dirty_pages_ratelimited(mapping);
 
-again:
 		/*
 		 * Bring in the user page that we will copy from _first_.
 		 * Otherwise there's a nasty deadlock on copying from the
@@ -4018,11 +4021,16 @@ again:
 		if (unlikely(status < 0))
 			break;
 
+		folio = page_folio(page);
+		offset = offset_in_folio(folio, pos);
+		if (bytes > folio_size(folio) - offset)
+			bytes = folio_size(folio) - offset;
+
 		if (mapping_writably_mapped(mapping))
-			flush_dcache_page(page);
+			flush_dcache_folio(folio);
 
-		copied = copy_page_from_iter_atomic(page, offset, bytes, i);
-		flush_dcache_page(page);
+		copied = copy_folio_from_iter_atomic(folio, offset, bytes, i);
+		flush_dcache_folio(folio);
 
 		status = a_ops->write_end(file, mapping, pos, bytes, copied,
 						page, fsdata);
@@ -4040,14 +4048,16 @@ again:
 			 * halfway through, might be a race with munmap,
 			 * might be severe memory pressure.
 			 */
-			if (copied)
+			if (chunk > PAGE_SIZE)
+				chunk /= 2;
+			if (copied) {
 				bytes = copied;
-			goto again;
+				goto retry;
+			}
+		} else {
+			pos += status;
+			written += status;
 		}
-		pos += status;
-		written += status;
-
-		balance_dirty_pages_ratelimited(mapping);
 	} while (iov_iter_count(i));
 
 	if (!written)