mm, hugetlb: improve, cleanup resv_map parameters

To change a protection method for region tracking to find grained one,
we pass the resv_map, instead of list_head, to region manipulation
functions.

This doesn't introduce any functional change, and it is just for
preparing a next step.

[davidlohr@hp.com: update changelog]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

@@ -151,8 +151,9 @@ struct file_region {
 	long to;
 };
 
-static long region_add(struct list_head *head, long f, long t)
+static long region_add(struct resv_map *resv, long f, long t)
 {
+	struct list_head *head = &resv->regions;
 	struct file_region *rg, *nrg, *trg;
 
 	/* Locate the region we are either in or before. */
@@ -187,8 +188,9 @@ static long region_add(struct list_head *head, long f, long t)
 	return 0;
 }
 
-static long region_chg(struct list_head *head, long f, long t)
+static long region_chg(struct resv_map *resv, long f, long t)
 {
+	struct list_head *head = &resv->regions;
 	struct file_region *rg, *nrg;
 	long chg = 0;
 
@@ -236,8 +238,9 @@ static long region_chg(struct list_head *head, long f, long t)
 	return chg;
 }
 
-static long region_truncate(struct list_head *head, long end)
+static long region_truncate(struct resv_map *resv, long end)
 {
+	struct list_head *head = &resv->regions;
 	struct file_region *rg, *trg;
 	long chg = 0;
 
@@ -266,8 +269,9 @@ static long region_truncate(struct list_head *head, long end)
 	return chg;
 }
 
-static long region_count(struct list_head *head, long f, long t)
+static long region_count(struct resv_map *resv, long f, long t)
 {
+	struct list_head *head = &resv->regions;
 	struct file_region *rg;
 	long chg = 0;
 
@@ -393,7 +397,7 @@ void resv_map_release(struct kref *ref)
 	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
 
 	/* Clear out any active regions before we release the map. */
-	region_truncate(&resv_map->regions, 0);
+	region_truncate(resv_map, 0);
 	kfree(resv_map);
 }
 
@@ -1152,7 +1156,7 @@ static long vma_needs_reservation(struct hstate *h,
 		pgoff_t idx = vma_hugecache_offset(h, vma, addr);
 		struct resv_map *resv = inode->i_mapping->private_data;
 
-		return region_chg(&resv->regions, idx, idx + 1);
+		return region_chg(resv, idx, idx + 1);
 
 	} else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
 		return 1;
@@ -1162,7 +1166,7 @@ static long vma_needs_reservation(struct hstate *h,
 		pgoff_t idx = vma_hugecache_offset(h, vma, addr);
 		struct resv_map *resv = vma_resv_map(vma);
 
-		err = region_chg(&resv->regions, idx, idx + 1);
+		err = region_chg(resv, idx, idx + 1);
 		if (err < 0)
 			return err;
 		return 0;
@@ -1178,14 +1182,14 @@ static void vma_commit_reservation(struct hstate *h,
 		pgoff_t idx = vma_hugecache_offset(h, vma, addr);
 		struct resv_map *resv = inode->i_mapping->private_data;
 
-		region_add(&resv->regions, idx, idx + 1);
+		region_add(resv, idx, idx + 1);
 
 	} else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
 		pgoff_t idx = vma_hugecache_offset(h, vma, addr);
 		struct resv_map *resv = vma_resv_map(vma);
 
 		/* Mark this page used in the map. */
-		region_add(&resv->regions, idx, idx + 1);
+		region_add(resv, idx, idx + 1);
 	}
 }
 
@@ -2276,7 +2280,7 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma)
 		end = vma_hugecache_offset(h, vma, vma->vm_end);
 
 		reserve = (end - start) -
-			region_count(&resv->regions, start, end);
+			region_count(resv, start, end);
 
 		resv_map_put(vma);
 
@@ -3178,7 +3182,7 @@ int hugetlb_reserve_pages(struct inode *inode,
 	if (!vma || vma->vm_flags & VM_MAYSHARE) {
 		resv_map = inode->i_mapping->private_data;
 
-		chg = region_chg(&resv_map->regions, from, to);
+		chg = region_chg(resv_map, from, to);
 
 	} else {
 		resv_map = resv_map_alloc();
@@ -3224,7 +3228,7 @@ int hugetlb_reserve_pages(struct inode *inode,
 	 * else has to be done for private mappings here
 	 */
 	if (!vma || vma->vm_flags & VM_MAYSHARE)
-		region_add(&resv_map->regions, from, to);
+		region_add(resv_map, from, to);
 	return 0;
 out_err:
 	if (vma)
@@ -3240,7 +3244,7 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
 	struct hugepage_subpool *spool = subpool_inode(inode);
 
 	if (resv_map)
-		chg = region_truncate(&resv_map->regions, offset);
+		chg = region_truncate(resv_map, offset);
 	spin_lock(&inode->i_lock);
 	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
 	spin_unlock(&inode->i_lock);