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From: Thomas Gleixner <tglx@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: "Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
	"André 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>,
	"Mark Brown" <broonie@kernel.org>,
	"Richard Weinberger" <richard@nod.at>
Subject: [patch V5 03/16] futex: Make futex_mm_init() void
Date: Tue, 02 Jun 2026 11:09:29 +0200	[thread overview]
Message-ID: <20260602090535.356789395@kernel.org> (raw)
In-Reply-To: 20260602084648.462672743@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
@@ -1101,6 +1101,7 @@ 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) {
@@ -1113,11 +1114,8 @@ 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;
@@ -1144,8 +1142,6 @@ 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
@@ -1720,7 +1720,7 @@ 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);
@@ -1729,7 +1729,6 @@ 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:[~2026-06-02  9:09 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-02  9:09 [patch V5 00/16] futex: Address the robust futex unlock race for real Thomas Gleixner
2026-06-02  9:09 ` [patch V5 01/16] percpu: Sanitize __percpu_qual include hell Thomas Gleixner
2026-06-03 14:25   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` [patch V5 02/16] futex: Move futex task related data into a struct Thomas Gleixner
2026-06-03 14:25   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` Thomas Gleixner [this message]
2026-06-03 14:25   ` [tip: locking/core] futex: Make futex_mm_init() void tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` [patch V5 04/16] futex: Move futex related mm_struct data into a struct Thomas Gleixner
2026-06-03 14:25   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` [patch V5 05/16] futex: Provide UABI defines for robust list entry modifiers Thomas Gleixner
2026-06-03 14:25   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` [patch V5 06/16] uaccess: Provide unsafe_atomic_store_release_user() Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` [patch V5 07/16] x86: Select ARCH_MEMORY_ORDER_TSO Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` [patch V5 08/16] futex: Cleanup UAPI defines Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` [patch V5 09/16] futex: Add support for unlocking robust futexes Thomas Gleixner
2026-06-03  8:22   ` Peter Zijlstra
2026-06-03  9:30     ` Peter Zijlstra
2026-06-03 14:40     ` Thomas Gleixner
2026-06-03  8:35   ` Peter Zijlstra
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:09 ` [patch V5 10/16] futex: Add robust futex unlock IP range Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:10 ` [patch V5 11/16] futex: Provide infrastructure to plug the non contended robust futex unlock race Thomas Gleixner
2026-06-03  8:42   ` Peter Zijlstra
2026-06-03  9:14   ` Peter Zijlstra
2026-06-03 14:47     ` Thomas Gleixner
2026-06-03  9:23   ` Peter Zijlstra
2026-06-03 14:42     ` Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:10 ` [patch V5 12/16] x86/vdso: Prepare for robust futex unlock support Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:10 ` [patch V5 13/16] x86/vdso: Implement __vdso_futex_robust_try_unlock() Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2026-06-02  9:10 ` [patch V5 14/16] Documentation: futex: Add a note about robust list race condition Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for André Almeida
2026-06-02  9:10 ` [patch V5 15/16] selftests: futex: Add tests for robust release operations Thomas Gleixner
2026-06-03 14:24   ` [tip: locking/core] " tip-bot2 for André Almeida
2026-06-02  9:10 ` [patch V5 16/16] [RFC] vdso, x86: Expose vdso.so.dbg through sysfs Thomas Gleixner
2026-06-02 10:39   ` Thomas Weißschuh
2026-06-02 20:02     ` Thomas Gleixner

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