From 2873cd31a20c25b5e763b35e5fb886f0938c6dd5 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Sat, 8 Jan 2022 10:03:24 -0600
Subject: [PATCH] exit: Remove profile_handoff_task
All profile_handoff_task does is notify the task_free_notifier chain.
The helpers task_handoff_register and task_handoff_unregister are used
to add and delete entries from that chain and are never called.
So remove the dead code and make it much easier to read and reason
about __put_task_struct.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/87fspyw6m0.fsf@email.froward.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
include/linux/profile.h | 19 -------------------
kernel/fork.c | 4 +---
kernel/profile.c | 23 -----------------------
3 files changed, 1 insertion(+), 45 deletions(-)
diff --git a/include/linux/profile.h b/include/linux/profile.h
index f7eb2b57d8908..11db1ec516e27 100644
--- a/include/linux/profile.h
+++ b/include/linux/profile.h
@@ -61,14 +61,6 @@ static inline void profile_hit(int type, void *ip)
struct task_struct;
struct mm_struct;
-/* task is dead, free task struct ? Returns 1 if
- * the task was taken, 0 if the task should be freed.
- */
-int profile_handoff_task(struct task_struct * task);
-
-int task_handoff_register(struct notifier_block * n);
-int task_handoff_unregister(struct notifier_block * n);
-
#else
#define prof_on 0
@@ -93,17 +85,6 @@ static inline void profile_hit(int type, void *ip)
return;
}
-static inline int task_handoff_register(struct notifier_block * n)
-{
- return -ENOSYS;
-}
-
-static inline int task_handoff_unregister(struct notifier_block * n)
-{
- return -ENOSYS;
-}
-
-#define profile_handoff_task(a) (0)
#endif /* CONFIG_PROFILING */
diff --git a/kernel/fork.c b/kernel/fork.c
index 6f0293cb29c96..494539ecb6d3b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -754,9 +754,7 @@ void __put_task_struct(struct task_struct *tsk)
delayacct_tsk_free(tsk);
put_signal_struct(tsk->signal);
sched_core_free(tsk);
-
- if (!profile_handoff_task(tsk))
- free_task(tsk);
+ free_task(tsk);
}
EXPORT_SYMBOL_GPL(__put_task_struct);
diff --git a/kernel/profile.c b/kernel/profile.c
index 9355cc934a965..37640a0bd8a3c 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -133,29 +133,6 @@ int __ref profile_init(void)
return -ENOMEM;
}
-/* Profile event notifications */
-
-static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
-
-int profile_handoff_task(struct task_struct *task)
-{
- int ret;
- ret = atomic_notifier_call_chain(&task_free_notifier, 0, task);
- return (ret == NOTIFY_OK) ? 1 : 0;
-}
-
-int task_handoff_register(struct notifier_block *n)
-{
- return atomic_notifier_chain_register(&task_free_notifier, n);
-}
-EXPORT_SYMBOL_GPL(task_handoff_register);
-
-int task_handoff_unregister(struct notifier_block *n)
-{
- return atomic_notifier_chain_unregister(&task_free_notifier, n);
-}
-EXPORT_SYMBOL_GPL(task_handoff_unregister);
-
#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
/*
* Each cpu has a pair of open-addressed hashtables for pending
--
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