rust: helpers: Avoid raw_spin_lock initialization for PREEMPT_RT

When PREEMPT_RT=y, spin locks are mapped to rt_mutex types, so using
spinlock_check() + __raw_spin_lock_init() to initialize spin locks is
incorrect, and would cause build errors.

Introduce __spin_lock_init() to initialize a spin lock with lockdep
rquired information for PREEMPT_RT builds, and use it in the Rust
helper.

Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.")
Closes: https://lore.kernel.org/oe-kbuild-all/202409251238.vetlgXE9-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Eder Zulian <ezulian@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20241107163223.2092690-2-ezulian@redhat.com

diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h
index f9f14e135be7b3ceca15a106cf2a2762ca069418..f6499c37157df2ba7147fadde305a53d50136eb4 100644 (file)
--- a/include/linux/spinlock_rt.h
+++ b/include/linux/spinlock_rt.h
@@ -16,22 +16,21 @@ static inline void __rt_spin_lock_init(spinlock_t *lock, const char *name,
 }
 #endif
 
-#define spin_lock_init(slock)                                  \
+#define __spin_lock_init(slock, name, key, percpu)             \
 do {                                                           \
-       static struct lock_class_key __key;                     \
-                                                               \
        rt_mutex_base_init(&(slock)->lock);                     \
-       __rt_spin_lock_init(slock, #slock, &__key, false);      \
+       __rt_spin_lock_init(slock, name, key, percpu);          \
 } while (0)
 
-#define local_spin_lock_init(slock)                            \
+#define _spin_lock_init(slock, percpu)                         \
 do {                                                           \
        static struct lock_class_key __key;                     \
-                                                               \
-       rt_mutex_base_init(&(slock)->lock);                     \
-       __rt_spin_lock_init(slock, #slock, &__key, true);       \
+       __spin_lock_init(slock, #slock, &__key, percpu);        \
 } while (0)
 
+#define spin_lock_init(slock)          _spin_lock_init(slock, false)
+#define local_spin_lock_init(slock)    _spin_lock_init(slock, true)
+
 extern void rt_spin_lock(spinlock_t *lock) __acquires(lock);
 extern void rt_spin_lock_nested(spinlock_t *lock, int subclass)        __acquires(lock);
 extern void rt_spin_lock_nest_lock(spinlock_t *lock, struct lockdep_map *nest_lock) __acquires(lock);

diff --git a/rust/helpers/spinlock.c b/rust/helpers/spinlock.c
index acc1376b833c786e7f7dde4b4179b750b80e02bd..92f7fc418425315d758eb9ec04be4542a8eaad6a 100644 (file)
--- a/rust/helpers/spinlock.c
+++ b/rust/helpers/spinlock.c
@@ -7,10 +7,14 @@ void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
                                  struct lock_class_key *key)
 {
 #ifdef CONFIG_DEBUG_SPINLOCK
+# if defined(CONFIG_PREEMPT_RT)
+       __spin_lock_init(lock, name, key, false);
+# else /*!CONFIG_PREEMPT_RT */
        __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
-#else
+# endif /* CONFIG_PREEMPT_RT */
+#else /* !CONFIG_DEBUG_SPINLOCK */
        spin_lock_init(lock);
-#endif
+#endif /* CONFIG_DEBUG_SPINLOCK */
 }
 
 void rust_helper_spin_lock(spinlock_t *lock)