pagewalk: separate function pointers from iterator data

The mm_walk structure currently mixed data and code.  Split out the
operations vectors into a new mm_walk_ops structure, and while we are
changing the API also declare the mm_walk structure inside the
walk_page_range and walk_page_vma functions.

Based on patch from Linus Torvalds.

Link: https://lore.kernel.org/r/20190828141955.22210-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 12 insertions, 29 deletions

diff --git a/mm/madvise.c b/mm/madvise.c
index 80a78bb16782..afe2b015ea58 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -226,19 +226,9 @@ static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
 	return 0;
 }
 
-static void force_swapin_readahead(struct vm_area_struct *vma,
-		unsigned long start, unsigned long end)
-{
-	struct mm_walk walk = {
-		.mm = vma->vm_mm,
-		.pmd_entry = swapin_walk_pmd_entry,
-		.private = vma,
-	};
-
-	walk_page_range(start, end, &walk);
-
-	lru_add_drain();	/* Push any new pages onto the LRU now */
-}
+static const struct mm_walk_ops swapin_walk_ops = {
+	.pmd_entry		= swapin_walk_pmd_entry,
+};
 
 static void force_shm_swapin_readahead(struct vm_area_struct *vma,
 		unsigned long start, unsigned long end,
@@ -280,7 +270,8 @@ static long madvise_willneed(struct vm_area_struct *vma,
 	*prev = vma;
 #ifdef CONFIG_SWAP
 	if (!file) {
-		force_swapin_readahead(vma, start, end);
+		walk_page_range(vma->vm_mm, start, end, &swapin_walk_ops, vma);
+		lru_add_drain(); /* Push any new pages onto the LRU now */
 		return 0;
 	}
 
@@ -441,20 +432,9 @@ next:
 	return 0;
 }
 
-static void madvise_free_page_range(struct mmu_gather *tlb,
-			     struct vm_area_struct *vma,
-			     unsigned long addr, unsigned long end)
-{
-	struct mm_walk free_walk = {
-		.pmd_entry = madvise_free_pte_range,
-		.mm = vma->vm_mm,
-		.private = tlb,
-	};
-
-	tlb_start_vma(tlb, vma);
-	walk_page_range(addr, end, &free_walk);
-	tlb_end_vma(tlb, vma);
-}
+static const struct mm_walk_ops madvise_free_walk_ops = {
+	.pmd_entry		= madvise_free_pte_range,
+};
 
 static int madvise_free_single_vma(struct vm_area_struct *vma,
 			unsigned long start_addr, unsigned long end_addr)
@@ -481,7 +461,10 @@ static int madvise_free_single_vma(struct vm_area_struct *vma,
 	update_hiwater_rss(mm);
 
 	mmu_notifier_invalidate_range_start(&range);
-	madvise_free_page_range(&tlb, vma, range.start, range.end);
+	tlb_start_vma(&tlb, vma);
+	walk_page_range(vma->vm_mm, range.start, range.end,
+			&madvise_free_walk_ops, &tlb);
+	tlb_end_vma(&tlb, vma);
 	mmu_notifier_invalidate_range_end(&range);
 	tlb_finish_mmu(&tlb, range.start, range.end);