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locking/ww_mutex: Add rt_mutex based lock type and accessors
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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
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Peter Zijlstra authored and Ingo Molnar committed Aug 17, 2021
1 parent 8850d77 commit 2408f7a
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Showing 2 changed files with 27 additions and 12 deletions.
33 changes: 24 additions & 9 deletions include/linux/ww_mutex.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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
};
Expand All @@ -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;
Expand Down Expand Up @@ -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
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -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))
/*
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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
}

/**
Expand Down
6 changes: 3 additions & 3 deletions kernel/locking/ww_mutex.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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)
Expand Down

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