From:   "Eric W. Biederman" <ebiederm@xmission.com>
To:     linux-kernel@vger.kernel.org
Cc:     linux-arch@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Al Viro <viro@ZenIV.linux.org.uk>,
        Kees Cook <keescook@chromium.org>, linux-api@vger.kernel.org,
        "Eric W. Biederman" <ebiederm@xmission.com>
Date:   Mon,  3 Jan 2022 15:32:56 -0600
Message-Id: <20220103213312.9144-1-ebiederm@xmission.com>
In-Reply-To: <87r19opkx1.fsf_-_@email.froward.int.ebiederm.org>
References: <87r19opkx1.fsf_-_@email.froward.int.ebiederm.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Subject: [PATCH 01/17] exit: Remove profile_task_exit & profile_munmap
Precedence: bulk

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