taskstats: split fill_pid function

Separate the finding of a task_struct by pid or tgid from filling the
taskstats data. This makes the code more readable.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 9970cae..c8231fb 100644 (file)
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -175,22 +175,8 @@ static void send_cpu_listeners(struct sk_buff *skb,
        up_write(&listeners->sem);
 }
 
-static int fill_pid(pid_t pid, struct task_struct *tsk,
-               struct taskstats *stats)
+static void fill_stats(struct task_struct *tsk, struct taskstats *stats)
 {
-       int rc = 0;
-
-       if (!tsk) {
-               rcu_read_lock();
-               tsk = find_task_by_vpid(pid);
-               if (tsk)
-                       get_task_struct(tsk);
-               rcu_read_unlock();
-               if (!tsk)
-                       return -ESRCH;
-       } else
-               get_task_struct(tsk);
-
        memset(stats, 0, sizeof(*stats));
        /*
         * Each accounting subsystem adds calls to its functions to
@@ -209,17 +195,27 @@ static int fill_pid(pid_t pid, struct task_struct *tsk,
 
        /* fill in extended acct fields */
        xacct_add_tsk(stats, tsk);
+}
 
-       /* Define err: label here if needed */
-       put_task_struct(tsk);
-       return rc;
+static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
+{
+       struct task_struct *tsk;
 
+       rcu_read_lock();
+       tsk = find_task_by_vpid(pid);
+       if (tsk)
+               get_task_struct(tsk);
+       rcu_read_unlock();
+       if (!tsk)
+               return -ESRCH;
+       fill_stats(tsk, stats);
+       put_task_struct(tsk);
+       return 0;
 }
 
-static int fill_tgid(pid_t tgid, struct task_struct *first,
-               struct taskstats *stats)
+static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats)
 {
-       struct task_struct *tsk;
+       struct task_struct *tsk, *first;
        unsigned long flags;
        int rc = -ESRCH;
 
@@ -228,8 +224,7 @@ static int fill_tgid(pid_t tgid, struct task_struct *first,
         * leaders who are already counted with the dead tasks
         */
        rcu_read_lock();
-       if (!first)
-               first = find_task_by_vpid(tgid);
+       first = find_task_by_vpid(tgid);
 
        if (!first || !lock_task_sighand(first, &flags))
                goto out;
@@ -268,7 +263,6 @@ out:
        return rc;
 }
 
-
 static void fill_tgid_exit(struct task_struct *tsk)
 {
        unsigned long flags;
@@ -483,7 +477,7 @@ static int cmd_attr_pid(struct genl_info *info)
        if (!stats)
                goto err;
 
-       rc = fill_pid(pid, NULL, stats);
+       rc = fill_stats_for_pid(pid, stats);
        if (rc < 0)
                goto err;
        return send_reply(rep_skb, info);
@@ -513,7 +507,7 @@ static int cmd_attr_tgid(struct genl_info *info)
        if (!stats)
                goto err;
 
-       rc = fill_tgid(tgid, NULL, stats);
+       rc = fill_stats_for_tgid(tgid, stats);
        if (rc < 0)
                goto err;
        return send_reply(rep_skb, info);
@@ -599,9 +593,7 @@ void taskstats_exit(struct task_struct *tsk, int group_dead)
        if (!stats)
                goto err;
 
-       rc = fill_pid(-1, tsk, stats);
-       if (rc < 0)
-               goto err;
+       fill_stats(tsk, stats);
 
        /*
         * Doesn't matter if tsk is the leader or the last group member leaving