mm: remove zap_page_range and create zap_vma_pages

zap_page_range was originally designed to unmap pages within an address
range that could span multiple vmas.  While working on [1], it was
discovered that all callers of zap_page_range pass a range entirely within
a single vma.  In addition, the mmu notification call within zap_page
range does not correctly handle ranges that span multiple vmas.  When
crossing a vma boundary, a new mmu_notifier_range_init/end call pair with
the new vma should be made.

Instead of fixing zap_page_range, do the following:
- Create a new routine zap_vma_pages() that will remove all pages within
  the passed vma.  Most users of zap_page_range pass the entire vma and
  can use this new routine.
- For callers of zap_page_range not passing the entire vma, instead call
  zap_page_range_single().
- Remove zap_page_range.

[1] https://lore.kernel.org/linux-mm/[email protected]/
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mike Kravetz <[email protected]>
Suggested-by: Peter Xu <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Peter Xu <[email protected]>
Acked-by: Heiko Carstens <[email protected]>	[s390]
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 5 insertions, 2 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4ac5ea4b584c..eb5bfc77c2c2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1977,10 +1977,13 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
 
 void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
 		  unsigned long size);
-void zap_page_range(struct vm_area_struct *vma, unsigned long address,
-		    unsigned long size);
 void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
 			   unsigned long size, struct zap_details *details);
+static inline void zap_vma_pages(struct vm_area_struct *vma)
+{
+	zap_page_range_single(vma, vma->vm_start,
+			      vma->vm_end - vma->vm_start, NULL);
+}
 void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt,
 		struct vm_area_struct *start_vma, unsigned long start,
 		unsigned long end);