futex: Create private_hash() get/put class

This gets us:

  fph = futex_private_hash(key) /* gets fph and inc users */
  futex_private_hash_get(fph)   /* inc users */
  futex_private_hash_put(fph)   /* dec users */

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250416162921.513656-8-bigeasy@linutronix.de

diff --git a/kernel/futex/core.c b/kernel/futex/core.c
index 56a5653e450cba5a1764a0d81d02ddb3d0cf65b2..6a1d6b14277f416c1f3808bd30725419f83186fe 100644 (file)
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -107,6 +107,18 @@ late_initcall(fail_futex_debugfs);
 
 #endif /* CONFIG_FAIL_FUTEX */
 
+struct futex_private_hash *futex_private_hash(void)
+{
+       return NULL;
+}
+
+bool futex_private_hash_get(struct futex_private_hash *fph)
+{
+       return false;
+}
+
+void futex_private_hash_put(struct futex_private_hash *fph) { }
+
 /**
  * futex_hash - Return the hash bucket in the global hash
  * @key:       Pointer to the futex key for which the hash is calculated

diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
index 77d9b3509f75ce5c659a86858492a9f9dd0ea489..bc76e366f9a7787d853d76aa681f2af26697a54e 100644 (file)
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -206,10 +206,18 @@ extern struct futex_hash_bucket *futex_hash(union futex_key *key);
 extern void futex_hash_get(struct futex_hash_bucket *hb);
 extern void futex_hash_put(struct futex_hash_bucket *hb);
 
+extern struct futex_private_hash *futex_private_hash(void);
+extern bool futex_private_hash_get(struct futex_private_hash *fph);
+extern void futex_private_hash_put(struct futex_private_hash *fph);
+
 DEFINE_CLASS(hb, struct futex_hash_bucket *,
             if (_T) futex_hash_put(_T),
             futex_hash(key), union futex_key *key);
 
+DEFINE_CLASS(private_hash, struct futex_private_hash *,
+            if (_T) futex_private_hash_put(_T),
+            futex_private_hash(), void);
+
 /**
  * futex_match - Check whether two futex keys are equal
  * @key1:      Pointer to key1