From: Chris Wilson Date: Wed, 11 Jul 2018 07:36:02 +0000 (+0100) Subject: drm/i915: Introduce i915_address_space.mutex X-Git-Tag: v4.19~298^2~26^2~56 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=19bb33c756edee5e3f0fb126895f6ec23e60dd08;p=platform%2Fkernel%2Flinux-rpi.git drm/i915: Introduce i915_address_space.mutex Add a mutex into struct i915_address_space to be used while operating on the vma and their lists for a particular vm. As this may be called from the shrinker, we taint the mutex with fs_reclaim so that from the start lockdep warns us if we are caught holding the mutex across an allocation. (With such small steps we will eventually rid ourselves of struct_mutex recursion!) Signed-off-by: Chris Wilson Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180711073608.20286-2-chris@chris-wilson.co.uk --- diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index a90a37c..48b3501 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -3307,7 +3307,7 @@ unsigned long i915_gem_shrink(struct drm_i915_private *i915, unsigned long i915_gem_shrink_all(struct drm_i915_private *i915); void i915_gem_shrinker_register(struct drm_i915_private *i915); void i915_gem_shrinker_unregister(struct drm_i915_private *i915); - +void i915_gem_shrinker_taints_mutex(struct mutex *mutex); /* i915_gem_tiling.c */ static inline bool i915_gem_object_needs_bit17_swizzle(struct drm_i915_gem_object *obj) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index 210baf3..502353b 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -531,6 +531,14 @@ static void vm_free_page(struct i915_address_space *vm, struct page *page) static void i915_address_space_init(struct i915_address_space *vm, struct drm_i915_private *dev_priv) { + /* + * The vm->mutex must be reclaim safe (for use in the shrinker). + * Do a dummy acquire now under fs_reclaim so that any allocation + * attempt holding the lock is immediately reported by lockdep. + */ + mutex_init(&vm->mutex); + i915_gem_shrinker_taints_mutex(&vm->mutex); + GEM_BUG_ON(!vm->total); drm_mm_init(&vm->mm, 0, vm->total); vm->mm.head_node.color = I915_COLOR_UNEVICTABLE; @@ -551,6 +559,8 @@ static void i915_address_space_fini(struct i915_address_space *vm) spin_unlock(&vm->free_pages.lock); drm_mm_takedown(&vm->mm); + + mutex_destroy(&vm->mutex); } static int __setup_page_dma(struct i915_address_space *vm, diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h index feda45d..14e6265 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.h +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h @@ -293,6 +293,8 @@ struct i915_address_space { bool closed; + struct mutex mutex; /* protects vma and our lists */ + struct i915_page_dma scratch_page; struct i915_page_table *scratch_pt; struct i915_page_directory *scratch_pd; diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c index c61f5b8..ea90d3a 100644 --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c @@ -23,6 +23,7 @@ */ #include +#include #include #include #include @@ -531,3 +532,14 @@ void i915_gem_shrinker_unregister(struct drm_i915_private *i915) WARN_ON(unregister_oom_notifier(&i915->mm.oom_notifier)); unregister_shrinker(&i915->mm.shrinker); } + +void i915_gem_shrinker_taints_mutex(struct mutex *mutex) +{ + if (!IS_ENABLED(CONFIG_LOCKDEP)) + return; + + fs_reclaim_acquire(GFP_KERNEL); + mutex_lock(mutex); + mutex_unlock(mutex); + fs_reclaim_release(GFP_KERNEL); +}