iomap: cleanup the pending writeback tracking in iomap_writepage_map_blocks

We don't care about the count of outstanding ioends, just if there is one.
Replace the count variable passed to iomap_writepage_map_blocks with a
boolean to make that more clear.

Signed-off-by: Joanne Koong <[email protected]>
[hch: rename the variable, update the commit message]
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Brian Foster <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Reviewed-by: "Darrick J. Wong" <[email protected]>

Author: joannekoong

fs/iomap/buffered-io.c

@@ -1748,7 +1748,7 @@ static int iomap_add_to_ioend(struct iomap_writepage_ctx *wpc,
 
 static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc,
 		struct folio *folio, u64 pos, u64 end_pos, unsigned dirty_len,
-		unsigned *count)
+		bool *wb_pending)
 {
 	int error;
 
@@ -1776,7 +1776,7 @@ static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc,
 			error = iomap_add_to_ioend(wpc, folio, pos, end_pos,
 					map_len);
 			if (!error)
-				(*count)++;
+				*wb_pending = true;
 			break;
 		}
 		dirty_len -= map_len;
@@ -1863,7 +1863,7 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc,
 	u64 pos = folio_pos(folio);
 	u64 end_pos = pos + folio_size(folio);
 	u64 end_aligned = 0;
-	unsigned count = 0;
+	bool wb_pending = false;
 	int error = 0;
 	u32 rlen;
 
@@ -1907,13 +1907,13 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc,
 	end_aligned = round_up(end_pos, i_blocksize(inode));
 	while ((rlen = iomap_find_dirty_range(folio, &pos, end_aligned))) {
 		error = iomap_writepage_map_blocks(wpc, folio, pos, end_pos,
-				rlen, &count);
+				rlen, &wb_pending);
 		if (error)
 			break;
 		pos += rlen;
 	}
 
-	if (count)
+	if (wb_pending)
 		wpc->nr_folios++;
 
 	/*
@@ -1935,7 +1935,7 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc,
 		if (atomic_dec_and_test(&ifs->write_bytes_pending))
 			folio_end_writeback(folio);
 	} else {
-		if (!count)
+		if (!wb_pending)
 			folio_end_writeback(folio);
 	}
 	mapping_set_error(inode->i_mapping, error);