linux-kernel - [PATCH 4/5] mm/vmalloc.c: Modify function merge_or_add_vmap

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Date:   Sun, 30 Jun 2019 15:56:49 +0800
From:   Pengfei Li <lpf.vector@...il.com>
To:     akpm@...ux-foundation.org, peterz@...radead.org, urezki@...il.com
Cc:     rpenyaev@...e.de, mhocko@...e.com, guro@...com,
        aryabinin@...tuozzo.com, rppt@...ux.ibm.com, mingo@...nel.org,
        rick.p.edgecombe@...el.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Pengfei Li <lpf.vector@...il.com>
Subject: [PATCH 4/5] mm/vmalloc.c: Modify function merge_or_add_vmap_area() for readability

Since function merge_or_add_vmap_area() is only used to
merge or add vmap area to the *FREE* tree, so rename it
to merge_or_add_va_to_free_tree.

Then this is obvious, merge_or_add_vmap_area() does not
need parameters root and head, so remove them.

Signed-off-by: Pengfei Li <lpf.vector@...il.com>
---
 mm/vmalloc.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 1beb5bcfb450..4148d6fdfb6d 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -688,8 +688,7 @@ insert_va_to_free_tree(struct vmap_area *va, struct rb_node *from)
  * freed.
  */
 static __always_inline void
-merge_or_add_vmap_area(struct vmap_area *va,
-	struct rb_root *root, struct list_head *head)
+merge_or_add_va_to_free_tree(struct vmap_area *va)
 {
 	struct vmap_area *sibling;
 	struct list_head *next;
@@ -701,7 +700,7 @@ merge_or_add_vmap_area(struct vmap_area *va,
 	 * Find a place in the tree where VA potentially will be
 	 * inserted, unless it is merged with its sibling/siblings.
 	 */
-	link = find_va_links(va, root, NULL, &parent);
+	link = find_va_links(va, &free_vmap_area_root, NULL, &parent);
 
 	/*
 	 * Get next node of VA to check if merging can be done.
@@ -717,7 +716,7 @@ merge_or_add_vmap_area(struct vmap_area *va,
 	 *                  |                |
 	 *                  start            end
 	 */
-	if (next != head) {
+	if (next != &free_vmap_area_list) {
 		sibling = list_entry(next, struct vmap_area, list);
 		if (sibling->va_start == va->va_end) {
 			sibling->va_start = va->va_start;
@@ -725,9 +724,6 @@ merge_or_add_vmap_area(struct vmap_area *va,
 			/* Check and update the tree if needed. */
 			augment_tree_propagate_from(sibling);
 
-			/* Remove this VA, it has been merged. */
-			unlink_va(va, root);
-
 			/* Free vmap_area object. */
 			kmem_cache_free(vmap_area_cachep, va);
 
@@ -744,7 +740,7 @@ merge_or_add_vmap_area(struct vmap_area *va,
 	 *                  |                |
 	 *                  start            end
 	 */
-	if (next->prev != head) {
+	if (next->prev != &free_vmap_area_list) {
 		sibling = list_entry(next->prev, struct vmap_area, list);
 		if (sibling->va_end == va->va_start) {
 			sibling->va_end = va->va_end;
@@ -753,7 +749,8 @@ merge_or_add_vmap_area(struct vmap_area *va,
 			augment_tree_propagate_from(sibling);
 
 			/* Remove this VA, it has been merged. */
-			unlink_va(va, root);
+			if (merged)
+				unlink_va(va, &free_vmap_area_root);
 
 			/* Free vmap_area object. */
 			kmem_cache_free(vmap_area_cachep, va);
@@ -764,7 +761,8 @@ merge_or_add_vmap_area(struct vmap_area *va,
 
 insert:
 	if (!merged) {
-		link_va(va, root, parent, link, head);
+		link_va(va, &free_vmap_area_root, parent, link,
+			&free_vmap_area_list);
 		augment_tree_propagate_from(va);
 	}
 }
@@ -1141,8 +1139,7 @@ static void __free_vmap_area(struct vmap_area *va)
 	/*
 	 * Merge VA with its neighbors, otherwise just add it.
 	 */
-	merge_or_add_vmap_area(va,
-		&free_vmap_area_root, &free_vmap_area_list);
+	merge_or_add_va_to_free_tree(va);
 }
 
 /*
-- 
2.21.0