[PATCH v9 05/37] mm: hugetlb: remove dead alloc_hugetlb_folio stub

[Michael S. Tsirkin]

Remove the !CONFIG_HUGETLB_PAGE stub for alloc_hugetlb_folio().

The stub is dead code: all callers are in mm/hugetlb.c
(CONFIG_HUGETLB_PAGE) or fs/hugetlbfs/inode.c (CONFIG_HUGETLBFS),
and CONFIG_HUGETLB_PAGE is def_bool HUGETLBFS with nothing
selecting it independently.

The stub is also broken: it returns NULL, but all callers check
IS_ERR(folio), so a NULL return would not be caught and would
crash on the subsequent folio dereference.

Remove it now since follow-up patches change the signature of
alloc_hugetlb_folio and would otherwise need to update the
broken stub too.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Reviewed-by: Gregory Price <gourry@xxxxxxxxxx>
Assisted-by: Claude:claude-opus-4-6
---
 include/linux/hugetlb.h | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 93418625d3c5..f016bc2e8936 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -1129,13 +1129,6 @@ static inline void wait_for_freed_hugetlb_folios(void)
 {
 }
 
-static inline struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
-					   unsigned long addr,
-					   bool cow_from_owner)
-{
-	return NULL;
-}
-
 static inline struct folio *
 alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid,
 			    nodemask_t *nmask, gfp_t gfp_mask)
-- 
MST