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Commit 19bb33c7 authored by Chris Wilson's avatar Chris Wilson
Browse files

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: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180711073608.20286-2-chris@chris-wilson.co.uk
parent 185441e0

drivers/gpu/drm/i915/i915_drv.h

+1 −1
Original line number Diff line number Diff line
@@ -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)

drivers/gpu/drm/i915/i915_gem_gtt.c

+10 −0
Original line number Diff line number Diff line
@@ -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,

drivers/gpu/drm/i915/i915_gem_gtt.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

drivers/gpu/drm/i915/i915_gem_shrinker.c

+12 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
 */



#include <linux/oom.h>

#include <linux/sched/mm.h>

#include <linux/shmem_fs.h>

#include <linux/slab.h>

#include <linux/swap.h>
@@ -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);

}