[PATCH] taskstats: cleanup do_exit() path

do_exit:
	taskstats_exit_alloc()
	...
	taskstats_exit_send()
	taskstats_exit_free()

I think this is not good, let it be a single function exported to the core
kernel, taskstats_exit(), which does alloc + send + free itself.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 19 insertions, 47 deletions

diff --git a/include/linux/taskstats_kern.h b/include/linux/taskstats_kern.h
index ce8a912e5426..f1261a532496 100644
--- a/include/linux/taskstats_kern.h
+++ b/include/linux/taskstats_kern.h
@@ -15,12 +15,6 @@
 extern struct kmem_cache *taskstats_cache;
 extern struct mutex taskstats_exit_mutex;
 
-static inline void taskstats_exit_free(struct taskstats *tidstats)
-{
-        if (tidstats)
-                kmem_cache_free(taskstats_cache, tidstats);
-}
-
 static inline void taskstats_tgid_init(struct signal_struct *sig)
 {
         sig->stats = NULL;
@@ -54,17 +48,10 @@ static inline void taskstats_tgid_free(struct signal_struct *sig)
                 kmem_cache_free(taskstats_cache, sig->stats);
 }
 
-extern void taskstats_exit_alloc(struct taskstats **, unsigned int *);
-extern void taskstats_exit_send(struct task_struct *, struct taskstats *, int, unsigned int);
+extern void taskstats_exit(struct task_struct *, int group_dead);
 extern void taskstats_init_early(void);
 #else
-static inline void taskstats_exit_alloc(struct taskstats **ptidstats, unsigned int *mycpu)
-{}
-static inline void taskstats_exit_free(struct taskstats *ptidstats)
-{}
-static inline void taskstats_exit_send(struct task_struct *tsk,
-                                       struct taskstats *tidstats,
-                                       int group_dead, unsigned int cpu)
+static inline void taskstats_exit(struct task_struct *tsk, int group_dead)
 {}
 static inline void taskstats_tgid_init(struct signal_struct *sig)
 {}
diff --git a/kernel/exit.c b/kernel/exit.c
index 06de6c4e8ca3..4e3f919edc48 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -850,9 +850,7 @@ static void exit_notify(struct task_struct *tsk)
 fastcall NORET_TYPE void do_exit(long code)
 {
         struct task_struct *tsk = current;
-        struct taskstats *tidstats;
         int group_dead;
-        unsigned int mycpu;
 
         profile_task_exit(tsk);
 
@@ -890,8 +888,6 @@ fastcall NORET_TYPE void do_exit(long code)
                                 current->comm, current->pid,
                                 preempt_count());
 
-        taskstats_exit_alloc(&tidstats, &mycpu);
-
         acct_update_integrals(tsk);
         if (tsk->mm) {
                 update_hiwater_rss(tsk->mm);
@@ -911,8 +907,8 @@ fastcall NORET_TYPE void do_exit(long code)
 #endif
         if (unlikely(tsk->audit_context))
                 audit_free(tsk);
-        taskstats_exit_send(tsk, tidstats, group_dead, mycpu);
-        taskstats_exit_free(tidstats);
+
+        taskstats_exit(tsk, group_dead);
 
         exit_mm(tsk);
 
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index d9d7c3576238..2654886fe058 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -119,10 +119,10 @@ static int send_reply(struct sk_buff *skb, pid_t pid)
 /*
  * Send taskstats data in @skb to listeners registered for @cpu's exit data
  */
-static void send_cpu_listeners(struct sk_buff *skb, unsigned int cpu)
+static void send_cpu_listeners(struct sk_buff *skb,
+                                        struct listener_list *listeners)
 {
         struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
-        struct listener_list *listeners;
         struct listener *s, *tmp;
         struct sk_buff *skb_next, *skb_cur = skb;
         void *reply = genlmsg_data(genlhdr);
@@ -135,7 +135,6 @@ static void send_cpu_listeners(struct sk_buff *skb, unsigned int cpu)
         }
 
         rc = 0;
-        listeners = &per_cpu(listener_array, cpu);
         down_read(&listeners->sem);
         list_for_each_entry(s, &listeners->list, list) {
                 skb_next = NULL;
@@ -413,28 +412,12 @@ err:
         return rc;
 }
 
-void taskstats_exit_alloc(struct taskstats **ptidstats, unsigned int *mycpu)
-{
-        struct listener_list *listeners;
-        /*
-         * This is the cpu on which the task is exiting currently and will
-         * be the one for which the exit event is sent, even if the cpu
-         * on which this function is running changes later.
-         */
-        *mycpu = raw_smp_processor_id();
-
-        listeners = &per_cpu(listener_array, *mycpu);
-
-        *ptidstats = NULL;
-        if (!list_empty(&listeners->list))
-                *ptidstats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
-}
-
 /* Send pid data out on exit */
-void taskstats_exit_send(struct task_struct *tsk, struct taskstats *tidstats,
-                        int group_dead, unsigned int mycpu)
+void taskstats_exit(struct task_struct *tsk, int group_dead)
 {
         int rc;
+        struct listener_list *listeners;
+        struct taskstats *tidstats;
         struct sk_buff *rep_skb;
         void *reply;
         size_t size;
@@ -458,12 +441,17 @@ void taskstats_exit_send(struct task_struct *tsk, struct taskstats *tidstats,
                 fill_tgid_exit(tsk);
         }
 
+        listeners = &__raw_get_cpu_var(listener_array);
+        if (list_empty(&listeners->list))
+                return;
+
+        tidstats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
         if (!tidstats)
                 return;
 
         rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, &reply, size);
         if (rc < 0)
-                goto ret;
+                goto free_stats;
 
         rc = fill_pid(tsk->pid, tsk, tidstats);
         if (rc < 0)
@@ -492,15 +480,16 @@ void taskstats_exit_send(struct task_struct *tsk, struct taskstats *tidstats,
         nla_nest_end(rep_skb, na);
 
 send:
-        send_cpu_listeners(rep_skb, mycpu);
+        send_cpu_listeners(rep_skb, listeners);
+free_stats:
+        kmem_cache_free(taskstats_cache, tidstats);
         return;
 
 nla_put_failure:
         genlmsg_cancel(rep_skb, reply);
 err_skb:
         nlmsg_free(rep_skb);
-ret:
-        return;
+        goto free_stats;
 }
 
 static struct genl_ops taskstats_ops = {