md-bitmap: split file writes into a separate helper

Split the file write code out of write_page into a separate helper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230615064840.629492-5-hch@lst.de

drivers/md/md-bitmap.c

@@ -296,33 +296,22 @@ static void write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 }
 
 static void md_bitmap_file_kick(struct bitmap *bitmap);
-/*
- * write out a page to a file
- */
-static void write_page(struct bitmap *bitmap, struct page *page, int wait)
-{
-	struct buffer_head *bh;
 
-	if (bitmap->storage.file == NULL) {
-		write_sb_page(bitmap, page, wait);
-	} else {
-
-		bh = page_buffers(page);
-
-		while (bh && bh->b_blocknr) {
-			atomic_inc(&bitmap->pending_writes);
-			set_buffer_locked(bh);
-			set_buffer_mapped(bh);
-			submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
-			bh = bh->b_this_page;
-		}
+static void write_file_page(struct bitmap *bitmap, struct page *page, int wait)
+{
+	struct buffer_head *bh = page_buffers(page);
 
-		if (wait)
-			wait_event(bitmap->write_wait,
-				   atomic_read(&bitmap->pending_writes)==0);
+	while (bh && bh->b_blocknr) {
+		atomic_inc(&bitmap->pending_writes);
+		set_buffer_locked(bh);
+		set_buffer_mapped(bh);
+		submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
+		bh = bh->b_this_page;
 	}
-	if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
-		md_bitmap_file_kick(bitmap);
+
+	if (wait)
+		wait_event(bitmap->write_wait,
+			   atomic_read(&bitmap->pending_writes) == 0);
 }
 
 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
@@ -429,6 +418,17 @@ static int read_page(struct file *file, unsigned long index,
  * bitmap file superblock operations
  */
 
+/*
+ * write out a page to a file
+ */
+static void write_page(struct bitmap *bitmap, struct page *page, int wait)
+{
+	if (bitmap->storage.file)
+		write_file_page(bitmap, page, wait);
+	else
+		write_sb_page(bitmap, page, wait);
+}
+
 /*
  * md_bitmap_wait_writes() should be called before writing any bitmap
  * blocks, to ensure previous writes, particularly from