locking/ww_mutex: Add rt_mutex based lock type and accessors

Provide the defines for RT mutex based ww_mutexes and fix up the debug logic
so it's either enabled by DEBUG_MUTEXES or DEBUG_RT_MUTEXES on RT kernels.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.908012566@linutronix.de

diff --git a/include/linux/ww_mutex.h b/include/linux/ww_mutex.h
index 3438e302a52a73c24dbab4b33f48a66205d47a52..29db736af86db6cd0985481ae6d08a3dff9e234d 100644 (file)
--- a/include/linux/ww_mutex.h
+++ b/include/linux/ww_mutex.h
@@ -18,11 +18,24 @@
 #define __LINUX_WW_MUTEX_H
 
 #include <linux/mutex.h>
+#include <linux/rtmutex.h>
 
+#if defined(CONFIG_DEBUG_MUTEXES) || \
+   (defined(CONFIG_PREEMPT_RT) && defined(CONFIG_DEBUG_RT_MUTEXES))
+#define DEBUG_WW_MUTEXES
+#endif
+
+#ifndef CONFIG_PREEMPT_RT
 #define WW_MUTEX_BASE                  mutex
 #define ww_mutex_base_init(l,n,k)      __mutex_init(l,n,k)
 #define ww_mutex_base_trylock(l)       mutex_trylock(l)
 #define ww_mutex_base_is_locked(b)     mutex_is_locked((b))
+#else
+#define WW_MUTEX_BASE                  rt_mutex
+#define ww_mutex_base_init(l,n,k)      __rt_mutex_init(l,n,k)
+#define ww_mutex_base_trylock(l)       rt_mutex_trylock(l)
+#define ww_mutex_base_is_locked(b)     rt_mutex_base_is_locked(&(b)->rtmutex)
+#endif
 
 struct ww_class {
        atomic_long_t stamp;
@@ -36,7 +49,7 @@ struct ww_class {
 struct ww_mutex {
        struct WW_MUTEX_BASE base;
        struct ww_acquire_ctx *ctx;
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        struct ww_class *ww_class;
 #endif
 };
@@ -47,10 +60,10 @@ struct ww_acquire_ctx {
        unsigned int acquired;
        unsigned short wounded;
        unsigned short is_wait_die;
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        unsigned int done_acquire;
        struct ww_class *ww_class;
-       struct ww_mutex *contending_lock;
+       void *contending_lock;
 #endif
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
        struct lockdep_map dep_map;
@@ -89,7 +102,7 @@ static inline void ww_mutex_init(struct ww_mutex *lock,
 {
        ww_mutex_base_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);
        lock->ctx = NULL;
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        lock->ww_class = ww_class;
 #endif
 }
@@ -126,7 +139,7 @@ static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
        ctx->acquired = 0;
        ctx->wounded = false;
        ctx->is_wait_die = ww_class->is_wait_die;
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        ctx->ww_class = ww_class;
        ctx->done_acquire = 0;
        ctx->contending_lock = NULL;
@@ -156,7 +169,7 @@ static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
  */
 static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
 {
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        lockdep_assert_held(ctx);
 
        DEBUG_LOCKS_WARN_ON(ctx->done_acquire);
@@ -176,7 +189,7 @@ static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
        mutex_release(&ctx->dep_map, _THIS_IP_);
 #endif
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        DEBUG_LOCKS_WARN_ON(ctx->acquired);
        if (!IS_ENABLED(CONFIG_PROVE_LOCKING))
                /*
@@ -282,7 +295,7 @@ static inline void
 ww_mutex_lock_slow(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
 {
        int ret;
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);
 #endif
        ret = ww_mutex_lock(lock, ctx);
@@ -318,7 +331,7 @@ static inline int __must_check
 ww_mutex_lock_slow_interruptible(struct ww_mutex *lock,
                                 struct ww_acquire_ctx *ctx)
 {
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);
 #endif
        return ww_mutex_lock_interruptible(lock, ctx);
@@ -348,7 +361,9 @@ static inline int __must_check ww_mutex_trylock(struct ww_mutex *lock)
  */
 static inline void ww_mutex_destroy(struct ww_mutex *lock)
 {
+#ifndef CONFIG_PREEMPT_RT
        mutex_destroy(&lock->base);
+#endif
 }
 
 /**

diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h
index 2dce4f0b0d1ced3b166246c0f23d953d1a7166e7..56f139201f2460b5586b28480b7357b419f531c5 100644 (file)
--- a/kernel/locking/ww_mutex.h
+++ b/kernel/locking/ww_mutex.h
@@ -180,7 +180,7 @@ static inline void lockdep_assert_wait_lock_held(struct rt_mutex *lock)
 static __always_inline void
 ww_mutex_lock_acquired(struct ww_mutex *ww, struct ww_acquire_ctx *ww_ctx)
 {
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
        /*
         * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
         * but released with a normal mutex_unlock in this call.
@@ -413,7 +413,7 @@ static __always_inline int
 __ww_mutex_kill(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx)
 {
        if (ww_ctx->acquired > 0) {
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
                struct ww_mutex *ww;
 
                ww = container_of(lock, struct ww_mutex, base);
@@ -559,7 +559,7 @@ __ww_mutex_add_waiter(struct MUTEX_WAITER *waiter,
 static inline void __ww_mutex_unlock(struct ww_mutex *lock)
 {
        if (lock->ctx) {
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef DEBUG_WW_MUTEXES
                DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
 #endif
                if (lock->ctx->acquired > 0)