[PATCH 01/17] exit: Remove profile_task_exit & profile_munmap

Eric W. Biederman
2022-01-03T21:33:35Z

When I say remove I mean remove. All profile_task_exit and
profile_munmap do is call a blocking notifier chain. The helpers
profile_task_register and profile_task_unregister are not called
anywhere in the tree. Which means this is all dead code.

So remove the dead code and make it easier to read do_exit.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
include/linux/profile.h | 26 ---------------------
kernel/exit.c | 1 -
kernel/profile.c | 50 -----------------------------------------
mm/mmap.c | 1 -
4 files changed, 78 deletions(-)

diff --git a/include/linux/profile.h b/include/linux/profile.h
index fd18ca96f557..f7eb2b57d890 100644
--- a/include/linux/profile.h
+++ b/include/linux/profile.h
@@ -31,11 +31,6 @@ static inline int create_proc_profile(void)
}
#endif

-enum profile_type {
- PROFILE_TASK_EXIT,
- PROFILE_MUNMAP
-};
-
#ifdef CONFIG_PROFILING

extern int prof_on __read_mostly;
@@ -66,23 +61,14 @@ static inline void profile_hit(int type, void *ip)
struct task_struct;
struct mm_struct;

-/* task is in do_exit() */
-void profile_task_exit(struct task_struct * task);
-
/* 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);

-/* sys_munmap */
-void profile_munmap(unsigned long addr);
-
int task_handoff_register(struct notifier_block * n);
int task_handoff_unregister(struct notifier_block * n);

-int profile_event_register(enum profile_type, struct notifier_block * n);
-int profile_event_unregister(enum profile_type, struct notifier_block * n);
-
#else

#define prof_on 0
@@ -117,19 +103,7 @@ static inline int task_handoff_unregister(struct notifier_block * n)
return -ENOSYS;
}

-static inline int profile_event_register(enum profile_type t, struct notifier_block * n)
-{
- return -ENOSYS;
-}
-
-static inline int profile_event_unregister(enum profile_type t, struct notifier_block * n)
-{
- return -ENOSYS;
-}
-
-#define profile_task_exit(a) do { } while (0)
#define profile_handoff_task(a) (0)
-#define profile_munmap(a) do { } while (0)

#endif /* CONFIG_PROFILING */

diff --git a/kernel/exit.c b/kernel/exit.c
index e7104f803be0..b5c35b520fda 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -737,7 +737,6 @@ void __noreturn do_exit(long code)

WARN_ON(blk_needs_flush_plug(tsk));

- profile_task_exit(tsk);
kcov_task_exit(tsk);

coredump_task_exit(tsk);
diff --git a/kernel/profile.c b/kernel/profile.c
index eb9c7f0f5ac5..9355cc934a96 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -135,14 +135,7 @@ int __ref profile_init(void)

/* Profile event notifications */

-static BLOCKING_NOTIFIER_HEAD(task_exit_notifier);
static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
-static BLOCKING_NOTIFIER_HEAD(munmap_notifier);
-
-void profile_task_exit(struct task_struct *task)
-{
- blocking_notifier_call_chain(&task_exit_notifier, 0, task);
-}

int profile_handoff_task(struct task_struct *task)
{
@@ -151,11 +144,6 @@ int profile_handoff_task(struct task_struct *task)
return (ret == NOTIFY_OK) ? 1 : 0;
}

-void profile_munmap(unsigned long addr)
-{
- blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr);
-}
-
int task_handoff_register(struct notifier_block *n)
{
return atomic_notifier_chain_register(&task_free_notifier, n);
@@ -168,44 +156,6 @@ int task_handoff_unregister(struct notifier_block *n)
}
EXPORT_SYMBOL_GPL(task_handoff_unregister);

-int profile_event_register(enum profile_type type, struct notifier_block *n)
-{
- int err = -EINVAL;
-
- switch (type) {
- case PROFILE_TASK_EXIT:
- err = blocking_notifier_chain_register(
- &task_exit_notifier, n);
- break;
- case PROFILE_MUNMAP:
- err = blocking_notifier_chain_register(
- &munmap_notifier, n);
- break;
- }
-
- return err;
-}
-EXPORT_SYMBOL_GPL(profile_event_register);
-
-int profile_event_unregister(enum profile_type type, struct notifier_block *n)
-{
- int err = -EINVAL;
-
- switch (type) {
- case PROFILE_TASK_EXIT:
- err = blocking_notifier_chain_unregister(
- &task_exit_notifier, n);
- break;
- case PROFILE_MUNMAP:
- err = blocking_notifier_chain_unregister(
- &munmap_notifier, n);
- break;
- }
-
- return err;
-}
-EXPORT_SYMBOL_GPL(profile_event_unregister);
-
#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
/*
* Each cpu has a pair of open-addressed hashtables for pending
diff --git a/mm/mmap.c b/mm/mmap.c
index bfb0ea164a90..70318c2a47c3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2928,7 +2928,6 @@ EXPORT_SYMBOL(vm_munmap);
SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
{
addr = untagged_addr(addr);
- profile_munmap(addr);
return __vm_munmap(addr, len, true);
}

--
2.29.2