Commit 279f2c2c authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Peter Zijlstra
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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: 094ac8cf ("futex: Relax the rcu_assign_pointer() assignment of mm->futex_phash in futex_mm_init()")
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250517151455.1065363-4-bigeasy@linutronix.de
parent 7d4f4947

include/linux/futex.h

+1 −8
Original line number Diff line number Diff line
@@ -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);

}