mm: thp: consolidate vma size check to transhuge_vma_suitable

There are couple of places that check whether the vma size is ok for THP
or whether address fits, they are open coded and duplicate, use
transhuge_vma_suitable() to do the job by passing in (vma->end -
HPAGE_PMD_SIZE).

Move vma size check into hugepage_vma_check().  This will make
khugepaged_enter() is as same as khugepaged_enter_vma().  There is just
one caller for khugepaged_enter(), replace it to khugepaged_enter_vma()
and remove khugepaged_enter().

Link: https://lkml.kernel.org/r/20220616174840.1202070-3-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 648cb3ce7099..8a5a8bfce0f5 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -116,6 +116,17 @@ extern struct kobj_attribute shmem_enabled_attr;
 
 extern unsigned long transparent_hugepage_flags;
 
+/*
+ * Do the below checks:
+ *   - For file vma, check if the linear page offset of vma is
+ *     HPAGE_PMD_NR aligned within the file.  The hugepage is
+ *     guaranteed to be hugepage-aligned within the file, but we must
+ *     check that the PMD-aligned addresses in the VMA map to
+ *     PMD-aligned offsets within the file, else the hugepage will
+ *     not be PMD-mappable.
+ *   - For all vmas, check if the haddr is in an aligned HPAGE_PMD_SIZE
+ *     area.
+ */
 static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
 		unsigned long addr)
 {