mm/sharepool: Update sp_mapping structure

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5DS9S
CVE: NA

-------------------------------------------------

1. Add a list for sp_mapping to record all the sp_groups attached to it.
2. Initialize the sp_mapping for local_group when it is created. So when
   we add a task to a group, we should merge the dvpp mapping of the
   local group.
3. Every two groups can be merged if and only if at least one of them is
   empty. Then the empty mapping would be dropped and another mapping
   would be attached to the two groups. This need to traverse all the
   groups attached to the mapping.
4. A mapping is considered empty when no spa is allocated from it and
   its address space is default.
Signed-off-by: NWang Wensheng <wangwensheng4@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/share_pool.h

@@ -117,6 +117,9 @@ struct sp_mapping {
 	struct rb_node *free_area_cache;
 	unsigned long cached_hole_size;
 	unsigned long cached_vstart;
+
+	/* list head for all groups attached to this mapping, dvpp mapping only */
+	struct list_head group_head;
 };
 
 /* Processes in the same sp_group can share memory.
@@ -160,8 +163,10 @@ struct sp_group {
 	atomic_t	 use_count;
 	/* protect the group internal elements, except spa_list */
 	struct rw_semaphore	rw_lock;
-	struct sp_mapping *dvpp;
-	struct sp_mapping *normal;
+	/* list node for dvpp mapping */
+	struct list_head	mnode;
+	struct sp_mapping	*dvpp;
+	struct sp_mapping	*normal;
 };
 
 /* a per-process(per mm) struct which manages a sp_group_node list */

mm/share_pool.c

@@ -168,6 +168,7 @@ static struct sp_mapping *sp_mapping_create(unsigned long flag)
 	sp_mapping_range_init(spm);
 	atomic_set(&spm->user, 0);
 	spm->area_root = RB_ROOT;
+	INIT_LIST_HEAD(&spm->group_head);
 
 	return spm;
 }
@@ -180,18 +181,45 @@ static void sp_mapping_destroy(struct sp_mapping *spm)
 static void sp_mapping_attach(struct sp_group *spg, struct sp_mapping *spm)
 {
 	atomic_inc(&spm->user);
-	if (spm->flag & SP_MAPPING_DVPP)
+	if (spm->flag & SP_MAPPING_DVPP) {
 		spg->dvpp = spm;
-	else if (spm->flag & SP_MAPPING_NORMAL)
+		list_add_tail(&spg->mnode, &spm->group_head);
+	} else if (spm->flag & SP_MAPPING_NORMAL)
 		spg->normal = spm;
 }
 
 static void sp_mapping_detach(struct sp_group *spg, struct sp_mapping *spm)
 {
-	if (spm && atomic_dec_and_test(&spm->user))
+	if (!spm)
+		return;
+	if (spm->flag & SP_MAPPING_DVPP)
+		list_del(&spg->mnode);
+	if (atomic_dec_and_test(&spm->user))
 		sp_mapping_destroy(spm);
 }
 
+/* merge old mapping to new, and the old mapping would be destroyed */
+static void sp_mapping_merge(struct sp_mapping *new, struct sp_mapping *old)
+{
+	struct sp_group *spg, *tmp;
+
+	if (new == old)
+		return;
+
+	list_for_each_entry_safe(spg, tmp, &old->group_head, mnode) {
+		list_move_tail(&spg->mnode, &new->group_head);
+		spg->dvpp = new;
+	}
+
+	atomic_add(atomic_read(&old->user), &new->user);
+	sp_mapping_destroy(old);
+}
+
+static bool is_mapping_empty(struct sp_mapping *spm)
+{
+	return RB_EMPTY_ROOT(&spm->area_root);
+}
+
 /*
  * When you set the address space of a group, the normal address space
  * is globally unified. When processing the DVPP address space, consider
@@ -216,32 +244,18 @@ static int sp_mapping_group_setup(struct mm_struct *mm, struct sp_group *spg)
 {
 	struct sp_group_master *master = mm->sp_group_master;
 	struct sp_group *local = master->local;
-	struct sp_mapping *spm;
 
 	if (!list_empty(&spg->procs)) {
-		/* 1 */
-		if (local->dvpp && local->dvpp != spg->dvpp) {
-			pr_info_ratelimited("Duplicate address space, id=%d\n",
-					spg->id);
-			return 0;
-		}
-
-		/* 2 */
-		if (!local->dvpp) {
-			sp_mapping_attach(local, spg->dvpp);
-			sp_mapping_attach(local, spg->normal);
+		if (is_mapping_empty(local->dvpp))
+			sp_mapping_merge(spg->dvpp, local->dvpp);
+		else if (is_mapping_empty(spg->dvpp))
+			sp_mapping_merge(local->dvpp, spg->dvpp);
+		else {
+			pr_info_ratelimited("Duplicate address space, id=%d\n", spg->id);
+			return -EINVAL;
 		}
 	} else {
-		/* 4 */
-		if (!local->dvpp) {
-			spm = sp_mapping_create(SP_MAPPING_DVPP);
-			if (IS_ERR(spm))
-				return PTR_ERR(spm);
-			sp_mapping_attach(local, spm);
-			sp_mapping_attach(local, sp_mapping_normal);
-		}
-
-		/* 3 */
+		/* the mapping of local group is always set */
 		sp_mapping_attach(spg, local->dvpp);
 		sp_mapping_attach(spg, sp_mapping_normal);
 	}
@@ -1121,6 +1135,7 @@ static struct sp_group *create_spg(int spg_id)
 	atomic_set(&spg->use_count, 1);
 	INIT_LIST_HEAD(&spg->procs);
 	INIT_LIST_HEAD(&spg->spa_list);
+	INIT_LIST_HEAD(&spg->mnode);
 	init_rwsem(&spg->rw_lock);
 
 	sprintf(name, "sp_group_%d", spg_id);