[patch V3 02/14] futex: Make futex_mm_init() void

Thomas Gleixner
2026-03-30T12:02:13Z

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)