smaps: add clear_refs file to clear reference

[powerpc.git] / fs / proc / base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 01f7769..ec158dd 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -715,6 +715,40 @@ static const struct file_operations proc_oom_adjust_operations = {
        .write          = oom_adjust_write,
 };
 
+static ssize_t clear_refs_write(struct file *file, const char __user *buf,
+                               size_t count, loff_t *ppos)
+{
+       struct task_struct *task;
+       char buffer[PROC_NUMBUF], *end;
+       struct mm_struct *mm;
+
+       memset(buffer, 0, sizeof(buffer));
+       if (count > sizeof(buffer) - 1)
+               count = sizeof(buffer) - 1;
+       if (copy_from_user(buffer, buf, count))
+               return -EFAULT;
+       if (!simple_strtol(buffer, &end, 0))
+               return -EINVAL;
+       if (*end == '\n')
+               end++;
+       task = get_proc_task(file->f_path.dentry->d_inode);
+       if (!task)
+               return -ESRCH;
+       mm = get_task_mm(task);
+       if (mm) {
+               clear_refs_smap(mm);
+               mmput(mm);
+       }
+       put_task_struct(task);
+       if (end - buffer == 0)
+               return -EIO;
+       return end - buffer;
+}
+
+static struct file_operations proc_clear_refs_operations = {
+       .write          = clear_refs_write,
+};
+
 #ifdef CONFIG_AUDITSYSCALL
 #define TMPBUFLEN 21
 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
@@ -1558,29 +1592,20 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
                                  size_t count, loff_t *ppos)
 {
        struct inode * inode = file->f_path.dentry->d_inode;
-       unsigned long page;
+       char *p = NULL;
        ssize_t length;
        struct task_struct *task = get_proc_task(inode);
 
-       length = -ESRCH;
        if (!task)
-               goto out_no_task;
-
-       if (count > PAGE_SIZE)
-               count = PAGE_SIZE;
-       length = -ENOMEM;
-       if (!(page = __get_free_page(GFP_KERNEL)))
-               goto out;
+               return -ESRCH;
 
        length = security_getprocattr(task,
                                      (char*)file->f_path.dentry->d_name.name,
-                                     (void*)page, count);
-       if (length >= 0)
-               length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
-       free_page(page);
-out:
+                                     &p);
        put_task_struct(task);
-out_no_task:
+       if (length > 0)
+               length = simple_read_from_buffer(buf, count, ppos, p, length);
+       kfree(p);
        return length;
 }
 
@@ -1860,6 +1885,7 @@ static struct pid_entry tgid_base_stuff[] = {
        REG("mounts",     S_IRUGO, mounts),
        REG("mountstats", S_IRUSR, mountstats),
 #ifdef CONFIG_MMU
+       REG("clear_refs", S_IWUSR, clear_refs),
        REG("smaps",      S_IRUGO, smaps),
 #endif
 #ifdef CONFIG_SECURITY
@@ -2141,6 +2167,7 @@ static struct pid_entry tid_base_stuff[] = {
        LNK("exe",       exe),
        REG("mounts",    S_IRUGO, mounts),
 #ifdef CONFIG_MMU
+       REG("clear_refs", S_IWUSR, clear_refs),
        REG("smaps",     S_IRUGO, smaps),
 #endif
 #ifdef CONFIG_SECURITY