[PATCH] taskstats: kill ->taskstats_lock in favor of ->siglock
signal_struct is (mostly) protected by ->sighand->siglock, I think we don't
need ->taskstats_lock to protect ->stats. This also allows us to simplify the
locking in fill_tgid().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/taskstats_kern.h b/include/linux/taskstats_kern.h
index 6642240..6562a20 100644
--- a/include/linux/taskstats_kern.h
+++ b/include/linux/taskstats_kern.h
@@ -23,28 +23,26 @@
static inline void taskstats_tgid_init(struct signal_struct *sig)
{
- spin_lock_init(&sig->stats_lock);
sig->stats = NULL;
}
-static inline void taskstats_tgid_alloc(struct signal_struct *sig)
+static inline void taskstats_tgid_alloc(struct task_struct *tsk)
{
+ struct signal_struct *sig = tsk->signal;
struct taskstats *stats;
- unsigned long flags;
if (sig->stats != NULL)
return;
+ /* No problem if kmem_cache_zalloc() fails */
stats = kmem_cache_zalloc(taskstats_cache, SLAB_KERNEL);
- if (!stats)
- return;
- spin_lock_irqsave(&sig->stats_lock, flags);
+ spin_lock_irq(&tsk->sighand->siglock);
if (!sig->stats) {
sig->stats = stats;
stats = NULL;
}
- spin_unlock_irqrestore(&sig->stats_lock, flags);
+ spin_unlock_irq(&tsk->sighand->siglock);
if (stats)
kmem_cache_free(taskstats_cache, stats);
@@ -59,7 +57,6 @@
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_init_early(void);
-extern void taskstats_tgid_alloc(struct signal_struct *);
#else
static inline void taskstats_exit_alloc(struct taskstats **ptidstats, unsigned int *mycpu)
{}
@@ -71,7 +68,7 @@
{}
static inline void taskstats_tgid_init(struct signal_struct *sig)
{}
-static inline void taskstats_tgid_alloc(struct signal_struct *sig)
+static inline void taskstats_tgid_alloc(struct task_struct *tsk)
{}
static inline void taskstats_tgid_free(struct signal_struct *sig)
{}