linux-kernel - [patch 05/12] futex: Split futex_mm

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Date:   Wed, 06 Nov 2019 22:55:39 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Darren Hart <darren@...art.com>,
        Yi Wang <wang.yi59@....com.cn>,
        Yang Tao <yang.tao172@....com.cn>,
        Oleg Nesterov <oleg@...hat.com>,
        Florian Weimer <fweimer@...hat.com>,
        Carlos O'Donell <carlos@...hat.com>,
        Alexander Viro <viro@...iv.linux.org.uk>
Subject: [patch 05/12] futex: Split futex_mm_release() for exit/exec

To allow separate handling of the futex exit state in the futex exit code
for exit and exec, split futex_mm_release() into two functions and invoke
them from the corresponding exit/exec_mm_release() callsites.

Preparatory only, no functional change.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 include/linux/futex.h |    6 ++++--
 kernel/fork.c         |    5 ++---
 kernel/futex.c        |    7 ++++++-
 3 files changed, 12 insertions(+), 6 deletions(-)

--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -91,14 +91,16 @@ static inline void futex_exit_done(struc
 	tsk->futex_state = FUTEX_STATE_DEAD;
 }
 
-void futex_mm_release(struct task_struct *tsk);
+void futex_exit_release(struct task_struct *tsk);
+void futex_exec_release(struct task_struct *tsk);
 
 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 	      u32 __user *uaddr2, u32 val2, u32 val3);
 #else
 static inline void futex_init_task(struct task_struct *tsk) { }
-static inline void futex_mm_release(struct task_struct *tsk) { }
 static inline void futex_exit_done(struct task_struct *tsk) { }
+static inline void futex_exit_release(struct task_struct *tsk) { }
+static inline void futex_exec_release(struct task_struct *tsk) { }
 static inline long do_futex(u32 __user *uaddr, int op, u32 val,
 			    ktime_t *timeout, u32 __user *uaddr2,
 			    u32 val2, u32 val3)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1285,9 +1285,6 @@ static int wait_for_vfork_done(struct ta
  */
 static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 {
-	/* Get rid of any futexes when releasing the mm */
-	futex_mm_release(tsk);
-
 	uprobe_free_utask(tsk);
 
 	/* Get rid of any cached register state */
@@ -1322,11 +1319,13 @@ static void mm_release(struct task_struc
 
 void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm)
 {
+	futex_exit_release(tsk);
 	mm_release(tsk, mm);
 }
 
 void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm)
 {
+	futex_exec_release(tsk);
 	mm_release(tsk, mm);
 }
 
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3661,7 +3661,7 @@ static void exit_robust_list(struct task
 	}
 }
 
-void futex_mm_release(struct task_struct *tsk)
+void futex_exec_release(struct task_struct *tsk)
 {
 	if (unlikely(tsk->robust_list)) {
 		exit_robust_list(tsk);
@@ -3679,6 +3679,11 @@ void futex_mm_release(struct task_struct
 		exit_pi_state_list(tsk);
 }
 
+void futex_exit_release(struct task_struct *tsk)
+{
+	futex_exec_release(tsk);
+}
+
 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 		u32 __user *uaddr2, u32 val2, u32 val3)
 {