From cf066e022d0091727f565ad15b42cbf52305d766 Mon Sep 17 00:00:00 2001
From: gatieme <gatieme@163.com>
Date: Sun, 8 May 2016 22:44:25 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AE=8C=E5=96=84=E4=BA=86=E9=81=8D=E5=8E=86?=
 =?UTF-8?q?=E6=89=80=E6=9C=89=E8=BF=9B=E7=A8=8B=E7=9A=84=E4=BB=A3=E7=A0=81?=
 =?UTF-8?q?...?=
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---
 study/process/find/find_task.c    | 17 +++++++++--------
 study/process/list/list_process.c |  8 ++++++++
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/study/process/find/find_task.c b/study/process/find/find_task.c
index 0a3a0db..437e8a1 100644
--- a/study/process/find/find_task.c
+++ b/study/process/find/find_task.c
@@ -40,7 +40,7 @@ static unsigned int PID = 1;
 module_param(PID, uint,0400);
 static int find_task_init(void)
 {
-    struct task_struct *task = NULL;
+    struct task_struct *task = NULL, *pTask = NULL;
     struct list_head *pos = NULL;
     char *method = NULL;
 
@@ -54,15 +54,16 @@ static int find_task_init(void)
     {
         case 1 :
             method = "list_for_each";
-            list_for_each(pos, &task->tasks )
+            list_for_each(pos, &task->tasks)
             {
-                task = list_entry(pos, struct task_struct, tasks );
-                if(task->pid == (pid_t)PID)
+                pTask = list_entry(pos, struct task_struct, tasks );
+                if(pTask->pid == (pid_t)PID)
                 {
-                    printk(KERN_ALERT "%d\t%s\t%p\n", task->pid, task->comm, task);
+                    printk(KERN_ALERT "%d\t%s\t%p\n", pTask->pid, pTask->comm, pTask);
                     break;
                 }
             }
+
             break;
         case 2 :
             method = "for_each_process";
@@ -77,11 +78,11 @@ static int find_task_init(void)
             break;
         case 3 :
             method = "list_for_each_entry";
-            list_for_each_entry(task, &task->tasks, tasks )
+            list_for_each_entry(pTask, &task->tasks, tasks)
             {
-                if(task->pid == PID)
+                if(pTask->pid == PID)
                 {
-                    printk(KERN_ALERT "%d\t%s\t%p\n", task->pid, task->comm, task);
+                    printk(KERN_ALERT "%d\t%s\t%p\n", pTask->pid, pTask->comm, pTask);
                 }
             }
     }
diff --git a/study/process/list/list_process.c b/study/process/list/list_process.c
index 9f56703..3fade23 100644
--- a/study/process/list/list_process.c
+++ b/study/process/list/list_process.c
@@ -42,6 +42,14 @@ static int list_process_init(void)
                 count++;
                 printk(KERN_ALERT "%d\t%s\n", pTask->pid, pTask->comm);
             }
+
+            //  because the list of process is an double-linked circular list
+            //  we can also list all the process from the current process
+            list_for_each(pos, &current->children)
+            {
+                pTask = list_entry(pos, struct task_struct, sibling);
+                printk(KERN_ALERT "%d\t%s\n", pTask->pid, pTask->comm);
+            }
             break;
         case 2 :
             method = "for_each_process";