svm: using a rbtree to manage the svm_process

ascend inclusion
category: feature
bugzilla: 16554
CVE: NA

--------

using a rbtree to manage a svm_process,and implement
find process, delete process and insert process
Signed-off-by: NJiankang Chen <chenjiankang1@huawei.com>
Signed-off-by: NLijun Fang <fanglijun3@huawei.com>
Reviewed-by: NLi Zefan <lizefan@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/char/svm.c

@@ -48,6 +48,7 @@ LIST_HEAD(child_list);
 #endif
 static DECLARE_RWSEM(svm_sem);
 static DEFINE_SPINLOCK(svm_process_lock);
+static struct rb_root svm_process_root = RB_ROOT;
 
 struct core_device {
 	struct device	dev;
@@ -114,18 +115,51 @@ static char *svm_cmd_to_string(unsigned int cmd)
 
 static struct svm_process *find_svm_process(unsigned long asid)
 {
-	/*TODO*/
+	struct rb_node *node = svm_process_root.rb_node;
+
+	while (node) {
+		struct svm_process *process = NULL;
+
+		process = rb_entry(node, struct svm_process, rb_node);
+		if (asid < process->asid)
+			node = node->rb_left;
+		else if (asid > process->asid)
+			node = node->rb_right;
+		else
+			return process;
+	}
+
 	return NULL;
 }
 
 static void insert_svm_process(struct svm_process *process)
 {
-	/*TODO*/
+	struct rb_node **p = &svm_process_root.rb_node;
+	struct rb_node *parent = NULL;
+
+	while (*p) {
+		struct svm_process *tmp_process = NULL;
+
+		parent = *p;
+		tmp_process = rb_entry(parent, struct svm_process, rb_node);
+		if (process->asid < tmp_process->asid)
+			p = &(*p)->rb_left;
+		else if (process->asid > tmp_process->asid)
+			p = &(*p)->rb_right;
+		else {
+			WARN_ON_ONCE("asid already in the tree");
+			return;
+		}
+	}
+
+	rb_link_node(&process->rb_node, parent, p);
+	rb_insert_color(&process->rb_node, &svm_process_root);
 }
 
 static void delete_svm_process(struct svm_process *process)
 {
-	/*TODO*/
+	rb_erase(&process->rb_node, &svm_process_root);
+	RB_CLEAR_NODE(&process->rb_node);
 }
 
 static struct svm_device *file_to_sdev(struct file *file)