1 files changed, 34 insertions, 4 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 9a6c2bfa1d9f..fea11c5c990c 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1686,7 +1686,7 @@ static struct inode_operations cgroup_dir_inode_operations = {
         .rename = cgroup_rename,
 };
 
-static int cgroup_create_file(struct dentry *dentry, int mode,
+static int cgroup_create_file(struct dentry *dentry, mode_t mode,
                                 struct super_block *sb)
 {
         static const struct dentry_operations cgroup_dops = {
@@ -1732,7 +1732,7 @@ static int cgroup_create_file(struct dentry *dentry, int mode,
  * @mode: mode to set on new directory.
  */
 static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry,
-                                int mode)
+                                mode_t mode)
 {
         struct dentry *parent;
         int error = 0;
@@ -1750,6 +1750,33 @@ static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry,
         return error;
 }
 
+/**
+ * cgroup_file_mode - deduce file mode of a control file
+ * @cft: the control file in question
+ *
+ * returns cft->mode if ->mode is not 0
+ * returns S_IRUGO|S_IWUSR if it has both a read and a write handler
+ * returns S_IRUGO if it has only a read handler
+ * returns S_IWUSR if it has only a write hander
+ */
+static mode_t cgroup_file_mode(const struct cftype *cft)
+{
+        mode_t mode = 0;
+
+        if (cft->mode)
+                return cft->mode;
+
+        if (cft->read || cft->read_u64 || cft->read_s64 ||
+            cft->read_map || cft->read_seq_string)
+                mode |= S_IRUGO;
+
+        if (cft->write || cft->write_u64 || cft->write_s64 ||
+            cft->write_string || cft->trigger)
+                mode |= S_IWUSR;
+
+        return mode;
+}
+
 int cgroup_add_file(struct cgroup *cgrp,
                        struct cgroup_subsys *subsys,
                        const struct cftype *cft)
@@ -1757,6 +1784,7 @@ int cgroup_add_file(struct cgroup *cgrp,
         struct dentry *dir = cgrp->dentry;
         struct dentry *dentry;
         int error;
+        mode_t mode;
 
         char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 };
         if (subsys && !test_bit(ROOT_NOPREFIX, &cgrp->root->flags)) {
@@ -1767,7 +1795,8 @@ int cgroup_add_file(struct cgroup *cgrp,
         BUG_ON(!mutex_is_locked(&dir->d_inode->i_mutex));
         dentry = lookup_one_len(name, dir, strlen(name));
         if (!IS_ERR(dentry)) {
-                error = cgroup_create_file(dentry, 0644 | S_IFREG,
+                mode = cgroup_file_mode(cft);
+                error = cgroup_create_file(dentry, mode | S_IFREG,
                                                 cgrp->root->sb);
                 if (!error)
                         dentry->d_fsdata = (void *)cft;
@@ -2349,6 +2378,7 @@ static struct cftype files[] = {
                 .write_u64 = cgroup_tasks_write,
                 .release = cgroup_tasks_release,
                 .private = FILE_TASKLIST,
+                .mode = S_IRUGO | S_IWUSR,
         },
 
         {
@@ -2449,7 +2479,7 @@ static void cgroup_unlock_hierarchy(struct cgroupfs_root *root)
  * Must be called with the mutex on the parent inode held
  */
 static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
-                             int mode)
+                             mode_t mode)
 {
         struct cgroup *cgrp;
         struct cgroupfs_root *root = parent->root;