From: Sebastian Andrzej Siewior Date: Sat, 17 May 2025 15:14:53 +0000 (+0200) Subject: futex: Use RCU_INIT_POINTER() in futex_mm_init(). X-Git-Tag: v6.16-rc1~199^2^2~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=279f2c2c8e2169403d01190f042efa6e41731578;p=thirdparty%2Fkernel%2Flinux.git futex: Use RCU_INIT_POINTER() in futex_mm_init(). There is no need for an explicit NULL pointer initialisation plus a comment why it is okay. RCU_INIT_POINTER() can be used for NULL initialisations and it is documented. This has been build tested with gcc version 9.3.0 (Debian 9.3.0-22) on a x86-64 defconfig. Fixes: 094ac8cff7858 ("futex: Relax the rcu_assign_pointer() assignment of mm->futex_phash in futex_mm_init()") Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20250517151455.1065363-4-bigeasy@linutronix.de --- diff --git a/include/linux/futex.h b/include/linux/futex.h index 168ffd5996b48..005b040c4791b 100644 --- a/include/linux/futex.h +++ b/include/linux/futex.h @@ -88,14 +88,7 @@ void futex_hash_free(struct mm_struct *mm); static inline void futex_mm_init(struct mm_struct *mm) { - /* - * No need for rcu_assign_pointer() here, as we can rely on - * tasklist_lock write-ordering in copy_process(), before - * the task's MM becomes visible and the ->futex_phash - * becomes externally observable: - */ - mm->futex_phash = NULL; - + RCU_INIT_POINTER(mm->futex_phash, NULL); mutex_init(&mm->futex_hash_lock); }