[PATCH 6/7] mm/filemap: allocate folios with mapping blocksize

[Hannes Reinecke <hare@suse.de>]

The mapping has an underlying blocksize (by virtue of
mapping->host->i_blkbits), so if the mapping blocksize
is larger than the pagesize we should allocate folios
in the correct order.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 include/linux/pagemap.h | 7 +++++++
 mm/filemap.c            | 7 ++++---
 mm/readahead.c          | 6 +++---
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 716953ee1ebd..9ea1a9724d64 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -494,6 +494,13 @@ static inline gfp_t readahead_gfp_mask(struct address_space *x)
 	return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
 }
 
+static inline int mapping_get_order(struct address_space *x)
+{
+	if (x->host->i_blkbits > PAGE_SHIFT)
+		return x->host->i_blkbits - PAGE_SHIFT;
+	return 0;
+}
+
 typedef int filler_t(struct file *, struct folio *);
 
 pgoff_t page_cache_next_miss(struct address_space *mapping,
diff --git a/mm/filemap.c b/mm/filemap.c
index 4be20e82e4c3..6f08d04995d9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1936,7 +1936,7 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
 			gfp |= GFP_NOWAIT | __GFP_NOWARN;
 		}
 
-		folio = filemap_alloc_folio(gfp, 0);
+		folio = filemap_alloc_folio(gfp, mapping_get_order(mapping));
 		if (!folio)
 			return ERR_PTR(-ENOMEM);
 
@@ -2495,7 +2495,8 @@ static int filemap_create_folio(struct file *file,
 	struct folio *folio;
 	int error;
 
-	folio = filemap_alloc_folio(mapping_gfp_mask(mapping), 0);
+	folio = filemap_alloc_folio(mapping_gfp_mask(mapping),
+				    mapping_get_order(mapping));
 	if (!folio)
 		return -ENOMEM;
 
@@ -3646,7 +3647,7 @@ static struct folio *do_read_cache_folio(struct address_space *mapping,
 repeat:
 	folio = filemap_get_folio(mapping, index);
 	if (IS_ERR(folio)) {
-		folio = filemap_alloc_folio(gfp, 0);
+		folio = filemap_alloc_folio(gfp, mapping_get_order(mapping));
 		if (!folio)
 			return ERR_PTR(-ENOMEM);
 		err = filemap_add_folio(mapping, folio, index, gfp);
diff --git a/mm/readahead.c b/mm/readahead.c
index 47afbca1d122..031935b78af7 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -245,7 +245,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
 			continue;
 		}
 
-		folio = filemap_alloc_folio(gfp_mask, 0);
+		folio = filemap_alloc_folio(gfp_mask, mapping_get_order(mapping));
 		if (!folio)
 			break;
 		if (filemap_add_folio(mapping, folio, index + i,
@@ -806,7 +806,7 @@ void readahead_expand(struct readahead_control *ractl,
 		if (folio && !xa_is_value(folio))
 			return; /* Folio apparently present */
 
-		folio = filemap_alloc_folio(gfp_mask, 0);
+		folio = filemap_alloc_folio(gfp_mask, mapping_get_order(mapping));
 		if (!folio)
 			return;
 		if (filemap_add_folio(mapping, folio, index, gfp_mask) < 0) {
@@ -833,7 +833,7 @@ void readahead_expand(struct readahead_control *ractl,
 		if (folio && !xa_is_value(folio))
 			return; /* Folio apparently present */
 
-		folio = filemap_alloc_folio(gfp_mask, 0);
+		folio = filemap_alloc_folio(gfp_mask, mapping_get_order(mapping));
 		if (!folio)
 			return;
 		if (filemap_add_folio(mapping, folio, index, gfp_mask) < 0) {
-- 
2.35.3