2 files changed, 122 insertions, 0 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index d65a1246829f..ca38db223f84 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -44,6 +44,9 @@
 #include <linux/string.h>
 #include <linux/sort.h>
 #include <linux/kmod.h>
+#include <linux/delayacct.h>
+#include <linux/cgroupstats.h>
+
 #include <asm/atomic.h>
 
 static DEFINE_MUTEX(cgroup_mutex);
@@ -1766,6 +1769,58 @@ static int pid_array_load(pid_t *pidarray, int npids, struct cgroup *cont)
         return n;
 }
 
+/**
+ * Build and fill cgroupstats so that taskstats can export it to user
+ * space.
+ *
+ * @stats: cgroupstats to fill information into
+ * @dentry: A dentry entry belonging to the cgroup for which stats have
+ * been requested.
+ */
+int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
+{
+        int ret = -EINVAL;
+        struct cgroup *cont;
+        struct cgroup_iter it;
+        struct task_struct *tsk;
+        /*
+         * Validate dentry by checking the superblock operations
+         */
+        if (dentry->d_sb->s_op != &cgroup_ops)
+                 goto err;
+
+        ret = 0;
+        cont = dentry->d_fsdata;
+        rcu_read_lock();
+
+        cgroup_iter_start(cont, &it);
+        while ((tsk = cgroup_iter_next(cont, &it))) {
+                switch (tsk->state) {
+                case TASK_RUNNING:
+                        stats->nr_running++;
+                        break;
+                case TASK_INTERRUPTIBLE:
+                        stats->nr_sleeping++;
+                        break;
+                case TASK_UNINTERRUPTIBLE:
+                        stats->nr_uninterruptible++;
+                        break;
+                case TASK_STOPPED:
+                        stats->nr_stopped++;
+                        break;
+                default:
+                        if (delayacct_is_task_waiting_on_io(tsk))
+                                stats->nr_io_wait++;
+                        break;
+                }
+        }
+        cgroup_iter_end(cont, &it);
+
+        rcu_read_unlock();
+err:
+        return ret;
+}
+
 static int cmppid(const void *a, const void *b)
 {
         return *(pid_t *)a - *(pid_t *)b;
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 7d4d7f9c1bb2..9f360f68aad6 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -22,6 +22,10 @@
 #include <linux/delayacct.h>
 #include <linux/cpumask.h>
 #include <linux/percpu.h>
+#include <linux/cgroupstats.h>
+#include <linux/cgroup.h>
+#include <linux/fs.h>
+#include <linux/file.h>
 #include <net/genetlink.h>
 #include <asm/atomic.h>
 
@@ -49,6 +53,11 @@ __read_mostly = {
         [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
         [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
 
+static struct nla_policy
+cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] __read_mostly = {
+        [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
+};
+
 struct listener {
         struct list_head list;
         pid_t pid;
@@ -372,6 +381,51 @@ err:
         return NULL;
 }
 
+static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
+{
+        int rc = 0;
+        struct sk_buff *rep_skb;
+        struct cgroupstats *stats;
+        struct nlattr *na;
+        size_t size;
+        u32 fd;
+        struct file *file;
+        int fput_needed;
+
+        na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
+        if (!na)
+                return -EINVAL;
+
+        fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
+        file = fget_light(fd, &fput_needed);
+        if (file) {
+                size = nla_total_size(sizeof(struct cgroupstats));
+
+                rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
+                                        size);
+                if (rc < 0)
+                        goto err;
+
+                na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
+                                        sizeof(struct cgroupstats));
+                stats = nla_data(na);
+                memset(stats, 0, sizeof(*stats));
+
+                rc = cgroupstats_build(stats, file->f_dentry);
+                if (rc < 0)
+                        goto err;
+
+                fput_light(file, fput_needed);
+                return send_reply(rep_skb, info->snd_pid);
+        }
+
+err:
+        if (file)
+                fput_light(file, fput_needed);
+        nlmsg_free(rep_skb);
+        return rc;
+}
+
 static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
 {
         int rc = 0;
@@ -522,6 +576,12 @@ static struct genl_ops taskstats_ops = {
         .policy         = taskstats_cmd_get_policy,
 };
 
+static struct genl_ops cgroupstats_ops = {
+        .cmd            = CGROUPSTATS_CMD_GET,
+        .doit           = cgroupstats_user_cmd,
+        .policy         = cgroupstats_cmd_get_policy,
+};
+
 /* Needed early in initialization */
 void __init taskstats_init_early(void)
 {
@@ -546,8 +606,15 @@ static int __init taskstats_init(void)
         if (rc < 0)
                 goto err;
 
+        rc = genl_register_ops(&family, &cgroupstats_ops);
+        if (rc < 0)
+                goto err_cgroup_ops;
+
         family_registered = 1;
+        printk("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
         return 0;
+err_cgroup_ops:
+        genl_unregister_ops(&family, &taskstats_ops);
 err:
         genl_unregister_family(&family);
         return rc;