mm: remove filemap_fdatawrite_wbc

Replace filemap_fdatawrite_wbc, which exposes a writeback_control to the
callers with a filemap_writeback helper that takes all the possible
arguments and declares the writeback_control itself.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20251024080431.324236-9-hch@lst.de
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Christoph Hellwig

fs/fs-writeback.c

@@ -822,9 +822,9 @@ static void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
  * @wbc: writeback_control of interest
  * @inode: target inode
  *
- * This function is to be used by __filemap_fdatawrite_range(), which is an
- * alternative entry point into writeback code, and first ensures @inode is
- * associated with a bdi_writeback and attaches it to @wbc.
+ * This function is to be used by filemap_writeback(), which is an alternative
+ * entry point into writeback code, and first ensures @inode is associated with
+ * a bdi_writeback and attaches it to @wbc.
  */
 void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
 		struct inode *inode)

include/linux/pagemap.h

@@ -60,8 +60,6 @@ int filemap_fdatawrite_range(struct address_space *mapping,
 		loff_t start, loff_t end);
 int filemap_check_errors(struct address_space *mapping);
 void __filemap_set_wb_err(struct address_space *mapping, int err);
-int filemap_fdatawrite_wbc(struct address_space *mapping,
-			   struct writeback_control *wbc);
 int kiocb_write_and_wait(struct kiocb *iocb, size_t count);
 
 static inline int filemap_write_and_wait(struct address_space *mapping)

mm/filemap.c

@@ -366,31 +366,30 @@ static int filemap_check_and_keep_errors(struct address_space *mapping)
 	return 0;
 }
 
-/**
- * filemap_fdatawrite_wbc - start writeback on mapping dirty pages in range
- * @mapping:	address space structure to write
- * @wbc:	the writeback_control controlling the writeout
- *
- * Call writepages on the mapping using the provided wbc to control the
- * writeout.
- *
- * Return: %0 on success, negative error code otherwise.
- */
-int filemap_fdatawrite_wbc(struct address_space *mapping,
-			   struct writeback_control *wbc)
+static int filemap_writeback(struct address_space *mapping, loff_t start,
+		loff_t end, enum writeback_sync_modes sync_mode,
+		long *nr_to_write)
 {
+	struct writeback_control wbc = {
+		.sync_mode	= sync_mode,
+		.nr_to_write	= nr_to_write ? *nr_to_write : LONG_MAX,
+		.range_start	= start,
+		.range_end	= end,
+	};
 	int ret;
 
 	if (!mapping_can_writeback(mapping) ||
 	    !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
 		return 0;
 
-	wbc_attach_fdatawrite_inode(wbc, mapping->host);
-	ret = do_writepages(mapping, wbc);
-	wbc_detach_inode(wbc);
+	wbc_attach_fdatawrite_inode(&wbc, mapping->host);
+	ret = do_writepages(mapping, &wbc);
+	wbc_detach_inode(&wbc);
+
+	if (!ret && nr_to_write)
+		*nr_to_write = wbc.nr_to_write;
 	return ret;
 }
-EXPORT_SYMBOL(filemap_fdatawrite_wbc);
 
 /**
  * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range
@@ -412,14 +411,7 @@ EXPORT_SYMBOL(filemap_fdatawrite_wbc);
 int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start,
 				loff_t end, int sync_mode)
 {
-	struct writeback_control wbc = {
-		.sync_mode = sync_mode,
-		.nr_to_write = LONG_MAX,
-		.range_start = start,
-		.range_end = end,
-	};
-
-	return filemap_fdatawrite_wbc(mapping, &wbc);
+	return filemap_writeback(mapping, start, end, sync_mode, NULL);
 }
 
 int filemap_fdatawrite_range(struct address_space *mapping, loff_t start,
@@ -475,18 +467,8 @@ EXPORT_SYMBOL(filemap_flush);
  */
 int filemap_flush_nr(struct address_space *mapping, long *nr_to_write)
 {
-	struct writeback_control wbc = {
-		.nr_to_write = *nr_to_write,
-		.sync_mode = WB_SYNC_NONE,
-		.range_start = 0,
-		.range_end = LLONG_MAX,
-	};
-	int ret;
-
-	ret = filemap_fdatawrite_wbc(mapping, &wbc);
-	if (!ret)
-		*nr_to_write = wbc.nr_to_write;
-	return ret;
+	return filemap_writeback(mapping, 0, LLONG_MAX, WB_SYNC_NONE,
+			nr_to_write);
 }
 EXPORT_SYMBOL_FOR_MODULES(filemap_flush_nr, "btrfs");