consolidate task->mm code + fix

diff -u -r1.1.1.1 array.c
@@ -277,15 +277,11 @@
 int proc_pid_status(struct task_struct *task, char * buffer)
 {
 	char * orig = buffer;
-	struct mm_struct *mm;
+	struct mm_struct *mm = get_task_mm(task);
 
 	buffer = task_name(task, buffer);
 	buffer = task_state(task, buffer);
-	task_lock(task);
-	mm = task->mm;
-	if(mm)
-		atomic_inc(&mm->mm_users);
-	task_unlock(task);
+ 
 	if (mm) {
 		buffer = task_mem(mm, buffer);
 		mmput(mm);

@@ -481,14 +477,9 @@
 
 int proc_pid_statm(struct task_struct *task, char * buffer)
 {
-	struct mm_struct *mm;
 	int size=0, resident=0, share=0, trs=0, lrs=0, drs=0, dt=0;
+	struct mm_struct *mm = get_task_mm(task);
 
-	task_lock(task);
-	mm = task->mm;
-	if(mm)
-		atomic_inc(&mm->mm_users);
-	task_unlock(task);
 	if (mm) {
 		struct vm_area_struct * vma;
 		down_read(&mm->mmap_sem);

@@ -626,11 +617,8 @@
 	if (!tmp)
 		goto out_free1;
 
-	task_lock(task);
-	mm = task->mm;
-	if (mm)
-		atomic_inc(&mm->mm_users);
-	task_unlock(task);
+	mm = get_task_mm(task);
+ 
 	retval = 0;
 	if (!mm)
 		goto out_free2;

175 lines not on this page · raw message

diff -u -r1.1.1.1.2.2 sched.h
@@ -810,6 +813,27 @@
 	return res;
 }
 
+ 
+/**
+ * get_task_mm - acquire a reference to the task's mm
+ *
+ * Returns %NULL if the task has no mm. User must release
+ * the mm via mmput() after use.
+ */
+static inline struct mm_struct * get_task_mm(struct task_struct * task)
+{
+	struct mm_struct * mm;
+ 
+	task_lock(task);
+	mm = task->mm;
+	if (mm)
+		atomic_inc(&mm->mm_users);
+	task_unlock(task);
+
+	return mm;
+}
+ 
+ 
 /* set thread flags in other task's structures
  * - see asm/thread_info.h for TIF_xxxx flags available
  */

diff -u -r1.1.1.1.2.1 ptrace.c
@@ -124,12 +124,7 @@
 	struct page *page;
 	void *old_buf = buf;
 
-	/* Worry about races with exit() */
-	task_lock(tsk);
-	mm = tsk->mm;
-	if (mm)
-		atomic_inc(&mm->mm_users);
-	task_unlock(tsk);
+	mm = get_task_mm(tsk);
 	if (!mm)
 		return 0;