trim task_work: get rid of hlist

layout based on Oleg's suggestion; single-linked list,
task->task_works points to the last element, forward pointer
from said last element points to head.  I'd still prefer
much more regular scheme with two pointers in task_work,
but...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 4 insertions, 4 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4059c0f33f0..b9216ebc278 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1405,7 +1405,7 @@ struct task_struct {
 	int (*notifier)(void *priv);
 	void *notifier_data;
 	sigset_t *notifier_mask;
-	struct hlist_head task_works;
+	void *task_works;
 
 	struct audit_context *audit_context;
 #ifdef CONFIG_AUDITSYSCALL
diff --git a/include/linux/task_work.h b/include/linux/task_work.h
index 627421c0e10..3b3e2c8d037 100644
--- a/include/linux/task_work.h
+++ b/include/linux/task_work.h
@@ -8,7 +8,7 @@ struct task_work;
 typedef void (*task_work_func_t)(struct task_work *);
 
 struct task_work {
-	struct hlist_node hlist;
+	struct task_work *next;
 	task_work_func_t func;
 };
 
@@ -24,7 +24,7 @@ void task_work_run(void);
 
 static inline void exit_task_work(struct task_struct *task)
 {
-	if (unlikely(!hlist_empty(&task->task_works)))
+	if (unlikely(task->task_works))
 		task_work_run();
 }
 
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 6a4d82bedb0..1e98b553042 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -192,7 +192,7 @@ static inline void tracehook_notify_resume(struct pt_regs *regs)
 	 * hlist_add_head(task->task_works);
 	 */
 	smp_mb__after_clear_bit();
-	if (unlikely(!hlist_empty(&current->task_works)))
+	if (unlikely(current->task_works))
 		task_work_run();
 }