Now that we can read asynchronously buffer heads from a folio in
chunks,  we can chop up bh_read_iter() with a smaller array size.
Use an array of 8 to avoid stack growth warnings on systems with
huge base page sizes.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 fs/buffer.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index b8ba72f2f211..bfa9c09b8597 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c

@@ -2415,7 +2415,10 @@ static void bh_read_batch_async(struct folio *folio,
          (__tmp);					\
          (__tmp) = bh_next(__tmp, __head))
 
+#define MAX_BUF_CHUNK 8
+
 struct bh_iter {
+	int chunk_number;
 	sector_t iblock;
 	get_block_t *get_block;
 	bool any_get_block_error;