mm/huge_memory: convert split_huge_pages_pid() from follow_page() to folio_walk

Let's remove yet another follow_page() user.  Note that we have to do the
split without holding the PTL, after folio_walk_end().  We don't care
about losing the secretmem check in follow_page().

[[email protected]: teach can_split_folio() that we are not holding an additional reference]
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Reviewed-by: Zi Yan <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Claudio Imbrenda <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Janosch Frank <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Ryan Roberts <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index e25d9ebfdf89..ce44caa40eed 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -314,7 +314,7 @@ unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long add
 		unsigned long len, unsigned long pgoff, unsigned long flags,
 		vm_flags_t vm_flags);
 
-bool can_split_folio(struct folio *folio, int *pextra_pins);
+bool can_split_folio(struct folio *folio, int caller_pins, int *pextra_pins);
 int split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
 		unsigned int new_order);
 static inline int split_huge_page(struct page *page)
@@ -470,7 +470,7 @@ thp_get_unmapped_area_vmflags(struct file *filp, unsigned long addr,
 }
 
 static inline bool
-can_split_folio(struct folio *folio, int *pextra_pins)
+can_split_folio(struct folio *folio, int caller_pins, int *pextra_pins)
 {
 	return false;
 }