diff options
| -rw-r--r-- | drivers/gpu/drm/drm_fb_helper.c | 10 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_modeset_lock.c | 56 | ||||
| -rw-r--r-- | include/drm/drm_modeset_lock.h | 6 |
3 files changed, 55 insertions, 17 deletions
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 3a6b6635e3f5..7b7b9565188f 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -365,11 +365,11 @@ static bool drm_fb_helper_force_kernel_mode(void) if (dev->switch_power_state == DRM_SWITCH_POWER_OFF) continue; - /* NOTE: we use lockless flag below to avoid grabbing other - * modeset locks. So just trylock the underlying mutex - * directly: + /* + * NOTE: Use trylock mode to avoid deadlocks and sleeping in + * panic context. */ - if (!mutex_trylock(&dev->mode_config.mutex)) { + if (__drm_modeset_lock_all(dev, true) != 0) { error = true; continue; } @@ -378,7 +378,7 @@ static bool drm_fb_helper_force_kernel_mode(void) if (ret) error = true; - mutex_unlock(&dev->mode_config.mutex); + drm_modeset_unlock_all(dev); } return error; } diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c index 4753c8bd5ab5..5280b64a0230 100644 --- a/drivers/gpu/drm/drm_modeset_lock.c +++ b/drivers/gpu/drm/drm_modeset_lock.c @@ -57,26 +57,37 @@ /** - * drm_modeset_lock_all - take all modeset locks - * @dev: drm device + * __drm_modeset_lock_all - internal helper to grab all modeset locks + * @dev: DRM device + * @trylock: trylock mode for atomic contexts * - * This function takes all modeset locks, suitable where a more fine-grained - * scheme isn't (yet) implemented. Locks must be dropped with - * drm_modeset_unlock_all. + * This is a special version of drm_modeset_lock_all() which can also be used in + * atomic contexts. Then @trylock must be set to true. + * + * Returns: + * 0 on success or negative error code on failure. */ -void drm_modeset_lock_all(struct drm_device *dev) +int __drm_modeset_lock_all(struct drm_device *dev, + bool trylock) { struct drm_mode_config *config = &dev->mode_config; struct drm_modeset_acquire_ctx *ctx; int ret; - ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); - if (WARN_ON(!ctx)) - return; + ctx = kzalloc(sizeof(*ctx), + trylock ? GFP_ATOMIC : GFP_KERNEL); + if (!ctx) + return -ENOMEM; - mutex_lock(&config->mutex); + if (trylock) { + if (!mutex_trylock(&config->mutex)) + return -EBUSY; + } else { + mutex_lock(&config->mutex); + } drm_modeset_acquire_init(ctx, 0); + ctx->trylock_only = trylock; retry: ret = drm_modeset_lock(&config->connection_mutex, ctx); @@ -95,13 +106,29 @@ retry: drm_warn_on_modeset_not_all_locked(dev); - return; + return 0; fail: if (ret == -EDEADLK) { drm_modeset_backoff(ctx); goto retry; } + + return ret; +} +EXPORT_SYMBOL(__drm_modeset_lock_all); + +/** + * drm_modeset_lock_all - take all modeset locks + * @dev: drm device + * + * This function takes all modeset locks, suitable where a more fine-grained + * scheme isn't (yet) implemented. Locks must be dropped with + * drm_modeset_unlock_all. + */ +void drm_modeset_lock_all(struct drm_device *dev) +{ + WARN_ON(__drm_modeset_lock_all(dev, false) != 0); } EXPORT_SYMBOL(drm_modeset_lock_all); @@ -287,7 +314,12 @@ static inline int modeset_lock(struct drm_modeset_lock *lock, WARN_ON(ctx->contended); - if (interruptible && slow) { + if (ctx->trylock_only) { + if (!ww_mutex_trylock(&lock->mutex)) + return -EBUSY; + else + return 0; + } else if (interruptible && slow) { ret = ww_mutex_lock_slow_interruptible(&lock->mutex, &ctx->ww_ctx); } else if (interruptible) { ret = ww_mutex_lock_interruptible(&lock->mutex, &ctx->ww_ctx); diff --git a/include/drm/drm_modeset_lock.h b/include/drm/drm_modeset_lock.h index d38e1508f11a..a3f736d24382 100644 --- a/include/drm/drm_modeset_lock.h +++ b/include/drm/drm_modeset_lock.h @@ -53,6 +53,11 @@ struct drm_modeset_acquire_ctx { * list of held locks (drm_modeset_lock) */ struct list_head locked; + + /** + * Trylock mode, use only for panic handlers! + */ + bool trylock_only; }; /** @@ -123,6 +128,7 @@ struct drm_device; struct drm_crtc; void drm_modeset_lock_all(struct drm_device *dev); +int __drm_modeset_lock_all(struct drm_device *dev, bool trylock); void drm_modeset_unlock_all(struct drm_device *dev); void drm_modeset_lock_crtc(struct drm_crtc *crtc); void drm_modeset_unlock_crtc(struct drm_crtc *crtc); |