mm/hugetlb: declare hugetlbfs_pagecache_present() non-static

It will be used outside hugetlb.c soon.

Link: https://lkml.kernel.org/r/20240327152332.950956-3-peterx@redhat.comSigned-off-by: Peter Xu <peterx@redhat.com>
Tested-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/hugetlb.h

@@ -174,6 +174,9 @@ u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx);
 
 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
 		      unsigned long addr, pud_t *pud);
+bool hugetlbfs_pagecache_present(struct hstate *h,
+				 struct vm_area_struct *vma,
+				 unsigned long address);
 
 struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage);
 
@@ -1228,6 +1231,12 @@ static inline void hugetlb_register_node(struct node *node)
 static inline void hugetlb_unregister_node(struct node *node)
 {
 }
+
+static inline bool hugetlbfs_pagecache_present(
+    struct hstate *h, struct vm_area_struct *vma, unsigned long address)
+{
+	return false;
+}
 #endif	/* CONFIG_HUGETLB_PAGE */
 
 static inline spinlock_t *huge_pte_lock(struct hstate *h,

mm/hugetlb.c

@@ -6113,8 +6113,8 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
 /*
  * Return whether there is a pagecache page to back given address within VMA.
  */
-static bool hugetlbfs_pagecache_present(struct hstate *h,
-			struct vm_area_struct *vma, unsigned long address)
+bool hugetlbfs_pagecache_present(struct hstate *h,
+				 struct vm_area_struct *vma, unsigned long address)
 {
 	struct address_space *mapping = vma->vm_file->f_mapping;
 	pgoff_t idx = linear_page_index(vma, address);