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From: Thomas Gleixner <tglx@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: "Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
	"Andrè Almeida" <andrealmeid@igalia.com>,
	"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
	"Carlos O'Donell" <carlos@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Florian Weimer" <fweimer@redhat.com>,
	"Rich Felker" <dalias@aerifal.cx>,
	"Torvald Riegel" <triegel@redhat.com>,
	"Darren Hart" <dvhart@infradead.org>,
	"Ingo Molnar" <mingo@kernel.org>,
	"Davidlohr Bueso" <dave@stgolabs.net>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Liam R . Howlett" <Liam.Howlett@oracle.com>,
	"Uros Bizjak" <ubizjak@gmail.com>,
	"Thomas Weißschuh" <linux@weissschuh.net>
Subject: [patch V3 02/14] futex: Make futex_mm_init() void
Date: Mon, 30 Mar 2026 14:02:09 +0200	[thread overview]
Message-ID: <20260330120117.194814100@kernel.org> (raw)
In-Reply-To: 20260330114212.927686587@kernel.org

Nothing fails there. Mop up the leftovers of the early version of this,
which did an allocation.

While at it clean up the stubs and the #ifdef comments to make the header
file readable.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
---
 include/linux/futex.h |   28 +++++++++++-----------------
 kernel/fork.c         |    8 ++------
 kernel/futex/core.c   |    3 +--
 3 files changed, 14 insertions(+), 25 deletions(-)

--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -81,22 +81,20 @@ int futex_hash_prctl(unsigned long arg2,
 #ifdef CONFIG_FUTEX_PRIVATE_HASH
 int futex_hash_allocate_default(void);
 void futex_hash_free(struct mm_struct *mm);
-int futex_mm_init(struct mm_struct *mm);
-
-#else /* !CONFIG_FUTEX_PRIVATE_HASH */
+void futex_mm_init(struct mm_struct *mm);
+#else  /* CONFIG_FUTEX_PRIVATE_HASH */
 static inline int futex_hash_allocate_default(void) { return 0; }
 static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
-static inline int futex_mm_init(struct mm_struct *mm) { return 0; }
-#endif /* CONFIG_FUTEX_PRIVATE_HASH */
+static inline void futex_mm_init(struct mm_struct *mm) { }
+#endif /* !CONFIG_FUTEX_PRIVATE_HASH */
 
-#else /* !CONFIG_FUTEX */
+#else  /* CONFIG_FUTEX */
 static inline void futex_init_task(struct task_struct *tsk) { }
 static inline void futex_exit_recursive(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)
+static inline long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
+			    u32 __user *uaddr2, u32 val2, u32 val3)
 {
 	return -EINVAL;
 }
@@ -104,13 +102,9 @@ static inline int futex_hash_prctl(unsig
 {
 	return -EINVAL;
 }
-static inline int futex_hash_allocate_default(void)
-{
-	return 0;
-}
+static inline int futex_hash_allocate_default(void) { return 0; }
 static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
-static inline int futex_mm_init(struct mm_struct *mm) { return 0; }
-
-#endif
+static inline void futex_mm_init(struct mm_struct *mm) { }
+#endif /* !CONFIG_FUTEX */
 
-#endif
+#endif /* _LINUX_FUTEX_H */
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1097,6 +1097,7 @@ static struct mm_struct *mm_init(struct
 #endif
 	mm_init_uprobes_state(mm);
 	hugetlb_count_init(mm);
+	futex_mm_init(mm);
 
 	mm_flags_clear_all(mm);
 	if (current->mm) {
@@ -1109,11 +1110,8 @@ static struct mm_struct *mm_init(struct
 		mm->def_flags = 0;
 	}
 
-	if (futex_mm_init(mm))
-		goto fail_mm_init;
-
 	if (mm_alloc_pgd(mm))
-		goto fail_nopgd;
+		goto fail_mm_init;
 
 	if (mm_alloc_id(mm))
 		goto fail_noid;
@@ -1140,8 +1138,6 @@ static struct mm_struct *mm_init(struct
 	mm_free_id(mm);
 fail_noid:
 	mm_free_pgd(mm);
-fail_nopgd:
-	futex_hash_free(mm);
 fail_mm_init:
 	free_mm(mm);
 	return NULL;
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -1717,7 +1717,7 @@ static bool futex_ref_is_dead(struct fut
 	return atomic_long_read(&mm->futex_atomic) == 0;
 }
 
-int futex_mm_init(struct mm_struct *mm)
+void futex_mm_init(struct mm_struct *mm)
 {
 	mutex_init(&mm->futex_hash_lock);
 	RCU_INIT_POINTER(mm->futex_phash, NULL);
@@ -1726,7 +1726,6 @@ int futex_mm_init(struct mm_struct *mm)
 	mm->futex_ref = NULL;
 	atomic_long_set(&mm->futex_atomic, 0);
 	mm->futex_batches = get_state_synchronize_rcu();
-	return 0;
 }
 
 void futex_hash_free(struct mm_struct *mm)


  parent reply	other threads:[~2026-03-30 12:02 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-30 12:01 [patch V3 00/14] futex: Address the robust futex unlock race for real Thomas Gleixner
2026-03-30 12:02 ` [patch V3 01/14] futex: Move futex task related data into a struct Thomas Gleixner
2026-03-30 12:02 ` Thomas Gleixner [this message]
2026-03-30 12:02 ` [patch V3 03/14] futex: Move futex related mm_struct " Thomas Gleixner
2026-03-30 15:23   ` Alexander Kuleshov
2026-03-30 12:02 ` [patch V3 04/14] futex: Provide UABI defines for robust list entry modifiers Thomas Gleixner
2026-03-30 12:02 ` [patch V3 05/14] uaccess: Provide unsafe_atomic_store_release_user() Thomas Gleixner
2026-03-30 13:33   ` Mark Rutland
2026-03-30 12:02 ` [patch V3 06/14] x86: Select ARCH_MEMORY_ORDER_TOS Thomas Gleixner
2026-03-30 13:34   ` Mark Rutland
2026-03-30 19:48     ` Thomas Gleixner
2026-03-30 12:02 ` [patch V3 07/14] futex: Cleanup UAPI defines Thomas Gleixner
2026-03-30 12:02 ` [patch V3 08/14] futex: Add support for unlocking robust futexes Thomas Gleixner
2026-03-30 12:02 ` [patch V3 09/14] futex: Add robust futex unlock IP range Thomas Gleixner
2026-03-30 12:02 ` [patch V3 10/14] futex: Provide infrastructure to plug the non contended robust futex unlock race Thomas Gleixner
2026-03-30 12:02 ` [patch V3 11/14] x86/vdso: Prepare for robust futex unlock support Thomas Gleixner
2026-03-30 12:03 ` [patch V3 12/14] x86/vdso: Implement __vdso_futex_robust_try_unlock() Thomas Gleixner
2026-03-30 12:03 ` [patch V3 13/14] Documentation: futex: Add a note about robust list race condition Thomas Gleixner
2026-03-30 12:03 ` [patch V3 14/14] selftests: futex: Add tests for robust release operations Thomas Gleixner
2026-03-30 13:45 ` [patch V3 00/14] futex: Address the robust futex unlock race for real Mark Rutland
2026-03-30 13:51   ` Peter Zijlstra
2026-03-30 19:36   ` Thomas Gleixner
2026-03-31 14:12     ` Mark Rutland
2026-03-31 12:59   ` André Almeida
2026-03-31 13:03     ` Sebastian Andrzej Siewior
2026-03-31 14:13     ` Mark Rutland
2026-03-31 15:22   ` Thomas Gleixner

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