[3/5] drm/i915: Add an implementation for i915_gem_ww_ctx locking.
diff mbox series

Message ID 20191206164317.2489743-4-maarten.lankhorst@linux.intel.com
State New
Headers show
Series
  • drm/i915/gem: Parallel execbuf WIP.
Related show

Commit Message

Maarten Lankhorst Dec. 6, 2019, 4:43 p.m. UTC
i915_gem_ww_ctx is used to lock all gem bo's for pinning and memory
eviction. We don't use it yet, but lets start adding the definition
first.

To use it, we have to pass a non-NULL ww to gem_object_lock, and don't
unlock directly. It is done in i915_gem_ww_ctx_fini.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c  |  6 +--
 drivers/gpu/drm/i915/display/intel_overlay.c  |  2 +-
 .../gpu/drm/i915/gem/i915_gem_client_blt.c    |  2 +-
 drivers/gpu/drm/i915/gem/i915_gem_context.c   |  2 +-
 drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c    |  4 +-
 drivers/gpu/drm/i915/gem/i915_gem_domain.c    | 10 ++--
 .../gpu/drm/i915/gem/i915_gem_execbuffer.c    |  4 +-
 drivers/gpu/drm/i915/gem/i915_gem_object.c    |  2 +-
 drivers/gpu/drm/i915/gem/i915_gem_object.h    | 38 ++++++++++---
 .../gpu/drm/i915/gem/i915_gem_object_blt.c    |  2 +-
 .../gpu/drm/i915/gem/i915_gem_object_types.h  |  9 ++++
 drivers/gpu/drm/i915/gem/i915_gem_pm.c        |  2 +-
 drivers/gpu/drm/i915/gem/i915_gem_tiling.c    |  2 +-
 .../gpu/drm/i915/gem/selftests/huge_pages.c   |  4 +-
 .../i915/gem/selftests/i915_gem_client_blt.c  |  2 +-
 .../i915/gem/selftests/i915_gem_coherency.c   | 10 ++--
 .../drm/i915/gem/selftests/i915_gem_context.c |  4 +-
 .../drm/i915/gem/selftests/i915_gem_mman.c    |  4 +-
 .../i915/gem/selftests/i915_gem_object_blt.c  |  4 +-
 .../drm/i915/gem/selftests/i915_gem_phys.c    |  2 +-
 .../gpu/drm/i915/gt/selftest_workarounds.c    |  2 +-
 drivers/gpu/drm/i915/gvt/cmd_parser.c         |  2 +-
 drivers/gpu/drm/i915/i915_gem.c               | 54 +++++++++++++++++--
 drivers/gpu/drm/i915/i915_gem.h               | 11 ++++
 drivers/gpu/drm/i915/selftests/i915_gem.c     | 41 ++++++++++++++
 drivers/gpu/drm/i915/selftests/i915_vma.c     |  2 +-
 .../drm/i915/selftests/intel_memory_region.c  |  4 +-
 27 files changed, 181 insertions(+), 50 deletions(-)

Patch
diff mbox series

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index eb0505a66ea8..c621b80d8d0f 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -2159,7 +2159,7 @@  intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
 	 * pin/unpin/fence and not more.
 	 */
 	wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 
 	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
 
@@ -2221,7 +2221,7 @@  intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
 
 void intel_unpin_fb_vma(struct i915_vma *vma, unsigned long flags)
 {
-	i915_gem_object_lock(vma->obj);
+	i915_gem_object_lock(NULL, vma->obj);
 	if (flags & PLANE_HAS_FENCE)
 		i915_vma_unpin_fence(vma);
 	i915_gem_object_unpin_from_display_plane(vma);
@@ -16348,7 +16348,7 @@  static int intel_framebuffer_init(struct intel_framebuffer *intel_fb,
 	if (!intel_fb->frontbuffer)
 		return -ENOMEM;
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	tiling = i915_gem_object_get_tiling(obj);
 	stride = i915_gem_object_get_stride(obj);
 	i915_gem_object_unlock(obj);
diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c
index 8cfb785e761c..5092d7d0b681 100644
--- a/drivers/gpu/drm/i915/display/intel_overlay.c
+++ b/drivers/gpu/drm/i915/display/intel_overlay.c
@@ -758,7 +758,7 @@  static int intel_overlay_do_put_image(struct intel_overlay *overlay,
 
 	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
 
-	i915_gem_object_lock(new_bo);
+	i915_gem_object_lock(NULL, new_bo);
 	vma = i915_gem_object_pin_to_display_plane(new_bo,
 						   0, NULL, PIN_MAPPABLE);
 	i915_gem_object_unlock(new_bo);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_client_blt.c b/drivers/gpu/drm/i915/gem/i915_gem_client_blt.c
index 81366aa4812b..d1b72c90fd83 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_client_blt.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_client_blt.c
@@ -287,7 +287,7 @@  int i915_gem_schedule_fill_pages_blt(struct drm_i915_gem_object *obj,
 	dma_fence_init(&work->dma, &clear_pages_work_ops, &fence_lock, 0, 0);
 	i915_sw_fence_init(&work->wait, clear_pages_work_notify);
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_sw_fence_await_reservation(&work->wait,
 					      obj->base.resv, NULL,
 					      true, I915_FENCE_TIMEOUT,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 9f1dc96b10a6..5b3a1aa3f66f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -114,7 +114,7 @@  static void lut_close(struct i915_gem_context *ctx)
 			continue;
 
 		rcu_read_unlock();
-		i915_gem_object_lock(obj);
+		i915_gem_object_lock(NULL, obj);
 		list_for_each_entry(lut, &obj->lut_list, obj_link) {
 			if (lut->ctx != ctx)
 				continue;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 372b57ca0efc..b7c46016820d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -124,7 +124,7 @@  static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, enum dma_data_dire
 	if (err)
 		return err;
 
-	err = i915_gem_object_lock_interruptible(obj);
+	err = i915_gem_object_lock_interruptible(NULL, obj);
 	if (err)
 		goto out;
 
@@ -145,7 +145,7 @@  static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direct
 	if (err)
 		return err;
 
-	err = i915_gem_object_lock_interruptible(obj);
+	err = i915_gem_object_lock_interruptible(NULL, obj);
 	if (err)
 		goto out;
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
index 808eb327a29b..31816bdcecaf 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
@@ -32,7 +32,7 @@  void i915_gem_object_flush_if_display(struct drm_i915_gem_object *obj)
 	if (!i915_gem_object_is_framebuffer(obj))
 		return;
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	__i915_gem_object_flush_for_display(obj);
 	i915_gem_object_unlock(obj);
 }
@@ -291,7 +291,7 @@  int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
 	if (ret)
 		goto out;
 
-	ret = i915_gem_object_lock_interruptible(obj);
+	ret = i915_gem_object_lock_interruptible(NULL, obj);
 	if (ret == 0) {
 		ret = i915_gem_object_set_cache_level(obj, level);
 		i915_gem_object_unlock(obj);
@@ -551,7 +551,7 @@  i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
 	if (err)
 		goto out;
 
-	err = i915_gem_object_lock_interruptible(obj);
+	err = i915_gem_object_lock_interruptible(NULL, obj);
 	if (err)
 		goto out_unpin;
 
@@ -591,7 +591,7 @@  int i915_gem_object_prepare_read(struct drm_i915_gem_object *obj,
 	if (!i915_gem_object_has_struct_page(obj))
 		return -ENODEV;
 
-	ret = i915_gem_object_lock_interruptible(obj);
+	ret = i915_gem_object_lock_interruptible(NULL, obj);
 	if (ret)
 		return ret;
 
@@ -645,7 +645,7 @@  int i915_gem_object_prepare_write(struct drm_i915_gem_object *obj,
 	if (!i915_gem_object_has_struct_page(obj))
 		return -ENODEV;
 
-	ret = i915_gem_object_lock_interruptible(obj);
+	ret = i915_gem_object_lock_interruptible(NULL, obj);
 	if (ret)
 		return ret;
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 50ba4933a7ae..02fdf081c1be 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -797,7 +797,7 @@  static int eb_lookup_vmas(struct i915_execbuffer *eb)
 		lut->handle = handle;
 		lut->ctx = eb->gem_context;
 
-		i915_gem_object_lock(obj);
+		i915_gem_object_lock(NULL, obj);
 		list_add(&lut->obj_link, &obj->lut_list);
 		i915_gem_object_unlock(obj);
 
@@ -1030,7 +1030,7 @@  static void *reloc_iomap(struct drm_i915_gem_object *obj,
 		if (use_cpu_reloc(cache, obj))
 			return NULL;
 
-		i915_gem_object_lock(obj);
+		i915_gem_object_lock(NULL, obj);
 		err = i915_gem_object_set_to_gtt_domain(obj, true);
 		i915_gem_object_unlock(obj);
 		if (err)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 16d611db9ca6..daee53fe6524 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -104,7 +104,7 @@  void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file)
 	struct i915_mmap_offset *mmo;
 	LIST_HEAD(close);
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	list_for_each_entry_safe(lut, ln, &obj->lut_list, obj_link) {
 		struct i915_gem_context *ctx = lut->ctx;
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index a1eb7c0b23ac..c7a554ae151e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -103,20 +103,44 @@  i915_gem_object_put(struct drm_i915_gem_object *obj)
 
 #define assert_object_held(obj) dma_resv_assert_held((obj)->base.resv)
 
-static inline void i915_gem_object_lock(struct drm_i915_gem_object *obj)
+static inline int __i915_gem_object_lock(struct i915_gem_ww_ctx *ww,
+					 struct drm_i915_gem_object *obj,
+					 bool intr)
 {
-	dma_resv_lock(obj->base.resv, NULL);
+	int ret;
+
+	if (intr)
+		ret = dma_resv_lock_interruptible(obj->base.resv, ww ? &ww->ctx : NULL);
+	else
+		ret = dma_resv_lock(obj->base.resv, ww ? &ww->ctx : NULL);
+
+	if (!ret && ww)
+		list_add_tail(&obj->obj_link, &ww->obj_list);
+	if (ret == -EALREADY)
+		ret = 0;
+
+	if (ret == -EDEADLK)
+		ww->contended = obj;
+
+	return ret;
 }
 
-static inline bool i915_gem_object_trylock(struct drm_i915_gem_object *obj)
+static inline int i915_gem_object_lock(struct i915_gem_ww_ctx *ww,
+				       struct drm_i915_gem_object *obj)
 {
-	return dma_resv_trylock(obj->base.resv);
+	return __i915_gem_object_lock(ww, obj, ww && ww->intr);
 }
 
-static inline int
-i915_gem_object_lock_interruptible(struct drm_i915_gem_object *obj)
+static inline int i915_gem_object_lock_interruptible(struct i915_gem_ww_ctx *ww,
+						     struct drm_i915_gem_object *obj)
 {
-	return dma_resv_lock_interruptible(obj->base.resv, NULL);
+	WARN_ON(ww && !ww->intr);
+	return __i915_gem_object_lock(ww, obj, true);
+}
+
+static inline bool i915_gem_object_trylock(struct drm_i915_gem_object *obj)
+{
+	return dma_resv_trylock(obj->base.resv);
 }
 
 static inline void i915_gem_object_unlock(struct drm_i915_gem_object *obj)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c b/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
index 70809d8897cd..b7c476813148 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
@@ -142,7 +142,7 @@  int i915_gem_object_fill_blt(struct drm_i915_gem_object *obj,
 		return err;
 
 	if (obj->cache_dirty & ~obj->cache_coherent) {
-		i915_gem_object_lock(obj);
+		i915_gem_object_lock(NULL, obj);
 		i915_gem_clflush_object(obj, 0);
 		i915_gem_object_unlock(obj);
 	}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index 2d404e6f63df..33a5ddda0285 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -122,6 +122,15 @@  struct drm_i915_gem_object {
 	 */
 	struct list_head lut_list;
 
+	/**
+	 * @obj_link: Link into @i915_gem_ww_ctx.obj_list
+	 *
+	 * When we lock this object through i915_gem_object_lock() with a
+	 * context, we add it to the list to ensure we can unlock everything
+	 * when i915_gem_ww_ctx_backoff() or i915_gem_ww_ctx_fini() are called.
+	 */
+	struct list_head obj_link;
+
 	/** Stolen memory for this object, instead of being backed by shmem. */
 	struct drm_mm_node *stolen;
 	union {
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_pm.c
index f88ee1317bb4..0f797843082b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pm.c
@@ -84,7 +84,7 @@  void i915_gem_suspend_late(struct drm_i915_private *i915)
 
 			spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 
-			i915_gem_object_lock(obj);
+			i915_gem_object_lock(NULL, obj);
 			WARN_ON(i915_gem_object_set_to_gtt_domain(obj, false));
 			i915_gem_object_unlock(obj);
 			i915_gem_object_put(obj);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_tiling.c b/drivers/gpu/drm/i915/gem/i915_gem_tiling.c
index 6c7825a2dc2a..a8e97f55839d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_tiling.c
@@ -236,7 +236,7 @@  i915_gem_object_set_tiling(struct drm_i915_gem_object *obj,
 	 * whilst executing a fenced command for an untiled object.
 	 */
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	if (i915_gem_object_is_framebuffer(obj)) {
 		i915_gem_object_unlock(obj);
 		return -EBUSY;
diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
index 3f992491f537..69cc6d39804f 100644
--- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
@@ -974,7 +974,7 @@  static int gpu_write(struct intel_context *ce,
 {
 	int err;
 
-	i915_gem_object_lock(vma->obj);
+	i915_gem_object_lock(NULL, vma->obj);
 	err = i915_gem_object_set_to_gtt_domain(vma->obj, true);
 	i915_gem_object_unlock(vma->obj);
 	if (err)
@@ -1022,7 +1022,7 @@  static int __cpu_check_lmem(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 	unsigned long n;
 	int err;
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_gem_object_set_to_wc_domain(obj, false);
 	i915_gem_object_unlock(obj);
 	if (err)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_client_blt.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_client_blt.c
index b972be165e85..f6f91a2a6cad 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_client_blt.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_client_blt.c
@@ -72,7 +72,7 @@  static int __igt_client_fill(struct intel_engine_cs *engine)
 		if (err)
 			goto err_unpin;
 
-		i915_gem_object_lock(obj);
+		i915_gem_object_lock(NULL, obj);
 		err = i915_gem_object_set_to_cpu_domain(obj, false);
 		i915_gem_object_unlock(obj);
 		if (err)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
index 49edc51111d5..7bbdd5bf1cec 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
@@ -82,7 +82,7 @@  static int gtt_set(struct context *ctx, unsigned long offset, u32 v)
 	u32 __iomem *map;
 	int err = 0;
 
-	i915_gem_object_lock(ctx->obj);
+	i915_gem_object_lock(NULL, ctx->obj);
 	err = i915_gem_object_set_to_gtt_domain(ctx->obj, true);
 	i915_gem_object_unlock(ctx->obj);
 	if (err)
@@ -115,7 +115,7 @@  static int gtt_get(struct context *ctx, unsigned long offset, u32 *v)
 	u32 __iomem *map;
 	int err = 0;
 
-	i915_gem_object_lock(ctx->obj);
+	i915_gem_object_lock(NULL, ctx->obj);
 	err = i915_gem_object_set_to_gtt_domain(ctx->obj, false);
 	i915_gem_object_unlock(ctx->obj);
 	if (err)
@@ -147,7 +147,7 @@  static int wc_set(struct context *ctx, unsigned long offset, u32 v)
 	u32 *map;
 	int err;
 
-	i915_gem_object_lock(ctx->obj);
+	i915_gem_object_lock(NULL, ctx->obj);
 	err = i915_gem_object_set_to_wc_domain(ctx->obj, true);
 	i915_gem_object_unlock(ctx->obj);
 	if (err)
@@ -168,7 +168,7 @@  static int wc_get(struct context *ctx, unsigned long offset, u32 *v)
 	u32 *map;
 	int err;
 
-	i915_gem_object_lock(ctx->obj);
+	i915_gem_object_lock(NULL, ctx->obj);
 	err = i915_gem_object_set_to_wc_domain(ctx->obj, false);
 	i915_gem_object_unlock(ctx->obj);
 	if (err)
@@ -191,7 +191,7 @@  static int gpu_set(struct context *ctx, unsigned long offset, u32 v)
 	u32 *cs;
 	int err;
 
-	i915_gem_object_lock(ctx->obj);
+	i915_gem_object_lock(NULL, ctx->obj);
 	err = i915_gem_object_set_to_gtt_domain(ctx->obj, true);
 	i915_gem_object_unlock(ctx->obj);
 	if (err)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
index 780e58fe5c64..d7b30daca5cb 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
@@ -950,7 +950,7 @@  emit_rpcs_query(struct drm_i915_gem_object *obj,
 	if (IS_ERR(vma))
 		return PTR_ERR(vma);
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_gem_object_set_to_gtt_domain(obj, false);
 	i915_gem_object_unlock(obj);
 	if (err)
@@ -1658,7 +1658,7 @@  static int read_from_scratch(struct i915_gem_context *ctx,
 
 	i915_request_add(rq);
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_gem_object_set_to_cpu_domain(obj, false);
 	i915_gem_object_unlock(obj);
 	if (err)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
index 591435c5f368..a956c927f469 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
@@ -102,7 +102,7 @@  static int check_partial_mapping(struct drm_i915_gem_object *obj,
 	GEM_BUG_ON(i915_gem_object_get_tiling(obj) != tile->tiling);
 	GEM_BUG_ON(i915_gem_object_get_stride(obj) != tile->stride);
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_gem_object_set_to_gtt_domain(obj, true);
 	i915_gem_object_unlock(obj);
 	if (err) {
@@ -187,7 +187,7 @@  static int check_partial_mappings(struct drm_i915_gem_object *obj,
 	GEM_BUG_ON(i915_gem_object_get_tiling(obj) != tile->tiling);
 	GEM_BUG_ON(i915_gem_object_get_stride(obj) != tile->stride);
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_gem_object_set_to_gtt_domain(obj, true);
 	i915_gem_object_unlock(obj);
 	if (err) {
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_object_blt.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_object_blt.c
index 62077fe46715..e23d8539de75 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_object_blt.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_object_blt.c
@@ -276,7 +276,7 @@  static int igt_fill_blt_thread(void *arg)
 		if (err)
 			goto err_unpin;
 
-		i915_gem_object_lock(obj);
+		i915_gem_object_lock(NULL, obj);
 		err = i915_gem_object_set_to_cpu_domain(obj, false);
 		i915_gem_object_unlock(obj);
 		if (err)
@@ -397,7 +397,7 @@  static int igt_copy_blt_thread(void *arg)
 		if (err)
 			goto err_unpin;
 
-		i915_gem_object_lock(dst);
+		i915_gem_object_lock(NULL, dst);
 		err = i915_gem_object_set_to_cpu_domain(dst, false);
 		i915_gem_object_unlock(dst);
 		if (err)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_phys.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_phys.c
index 34932871b3a5..262d5fd443c1 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_phys.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_phys.c
@@ -44,7 +44,7 @@  static int mock_phys_object(void *arg)
 	}
 
 	/* Make the object dirty so that put_pages must do copy back the data */
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_gem_object_set_to_gtt_domain(obj, true);
 	i915_gem_object_unlock(obj);
 	if (err) {
diff --git a/drivers/gpu/drm/i915/gt/selftest_workarounds.c b/drivers/gpu/drm/i915/gt/selftest_workarounds.c
index d5d1e1a32187..5891e9eb9a74 100644
--- a/drivers/gpu/drm/i915/gt/selftest_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/selftest_workarounds.c
@@ -214,7 +214,7 @@  static int check_whitelist(struct i915_gem_context *ctx,
 		return PTR_ERR(results);
 
 	err = 0;
-	i915_gem_object_lock(results);
+	i915_gem_object_lock(NULL, results);
 	intel_wedge_on_timeout(&wedge, engine->gt, HZ / 5) /* safety net! */
 		err = i915_gem_object_set_to_cpu_domain(results, false);
 	i915_gem_object_unlock(results);
diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c b/drivers/gpu/drm/i915/gvt/cmd_parser.c
index 21a176cd8acc..85cde10520e4 100644
--- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
+++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
@@ -2954,7 +2954,7 @@  static int shadow_indirect_ctx(struct intel_shadow_wa_ctx *wa_ctx)
 		goto put_obj;
 	}
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	ret = i915_gem_object_set_to_cpu_domain(obj, false);
 	i915_gem_object_unlock(obj);
 	if (ret) {
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 919d3a723c50..9d74fda4c0f6 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -412,7 +412,7 @@  i915_gem_gtt_pread(struct drm_i915_gem_object *obj,
 		GEM_BUG_ON(!drm_mm_node_allocated(&node));
 	}
 
-	ret = i915_gem_object_lock_interruptible(obj);
+	ret = i915_gem_object_lock_interruptible(NULL, obj);
 	if (ret)
 		goto out_unpin;
 
@@ -611,7 +611,7 @@  i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj,
 		GEM_BUG_ON(!drm_mm_node_allocated(&node));
 	}
 
-	ret = i915_gem_object_lock_interruptible(obj);
+	ret = i915_gem_object_lock_interruptible(NULL, obj);
 	if (ret)
 		goto out_unpin;
 
@@ -1194,7 +1194,7 @@  static int __intel_engines_record_defaults(struct intel_gt *gt)
 		if (err)
 			goto out;
 
-		i915_gem_object_lock(state->obj);
+		i915_gem_object_lock(NULL, state->obj);
 		err = i915_gem_object_set_to_cpu_domain(state->obj, false);
 		i915_gem_object_unlock(state->obj);
 		if (err)
@@ -1508,7 +1508,7 @@  int i915_gem_freeze_late(struct drm_i915_private *i915)
 	i915_gem_drain_freed_objects(i915);
 
 	list_for_each_entry(obj, &i915->mm.shrink_list, mm.link) {
-		i915_gem_object_lock(obj);
+		i915_gem_object_lock(NULL, obj);
 		WARN_ON(i915_gem_object_set_to_cpu_domain(obj, true));
 		i915_gem_object_unlock(obj);
 	}
@@ -1561,6 +1561,52 @@  int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file)
 	return ret;
 }
 
+void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ww, bool intr)
+{
+	ww_acquire_init(&ww->ctx, &reservation_ww_class);
+	INIT_LIST_HEAD(&ww->obj_list);
+	ww->intr = intr;
+	ww->contended = NULL;
+}
+
+static void i915_gem_ww_ctx_unlock_all(struct i915_gem_ww_ctx *ww)
+{
+	struct drm_i915_gem_object *obj;
+
+	while ((obj = list_first_entry_or_null(&ww->obj_list, struct drm_i915_gem_object, obj_link))) {
+		list_del(&obj->obj_link);
+		i915_gem_object_unlock(obj);
+	}
+}
+
+void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ww)
+{
+	i915_gem_ww_ctx_unlock_all(ww);
+	WARN_ON(ww->contended);
+	ww_acquire_fini(&ww->ctx);
+}
+
+int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ww)
+{
+	int ret = 0;
+
+	if (WARN_ON(!ww->contended))
+		return -EINVAL;
+
+	i915_gem_ww_ctx_unlock_all(ww);
+	if (ww->intr)
+		ret = dma_resv_lock_slow_interruptible(ww->contended->base.resv, &ww->ctx);
+	else
+		dma_resv_lock_slow(ww->contended->base.resv, &ww->ctx);
+
+	if (!ret)
+		list_add_tail(&ww->contended->obj_link, &ww->obj_list);
+
+	ww->contended = NULL;
+
+	return ret;
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/mock_gem_device.c"
 #include "selftests/i915_gem.c"
diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 1753c84d6c0d..988755dbf4be 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -116,4 +116,15 @@  static inline bool __tasklet_is_scheduled(struct tasklet_struct *t)
 	return test_bit(TASKLET_STATE_SCHED, &t->state);
 }
 
+struct i915_gem_ww_ctx {
+	struct ww_acquire_ctx ctx;
+	struct list_head obj_list;
+	bool intr;
+	struct drm_i915_gem_object *contended;
+};
+
+void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ctx, bool intr);
+void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ctx);
+int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ctx);
+
 #endif /* __I915_GEM_H__ */
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem.c b/drivers/gpu/drm/i915/selftests/i915_gem.c
index 657e23a8dd11..f4e74873462b 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem.c
@@ -202,11 +202,52 @@  static int igt_gem_hibernate(void *arg)
 	return err;
 }
 
+static int igt_gem_ww_ctx(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct drm_i915_gem_object *obj, *obj2;
+	struct i915_gem_ww_ctx ww;
+	int err = 0;
+
+	obj = i915_gem_object_create_internal(i915, PAGE_SIZE);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	obj = i915_gem_object_create_internal(i915, PAGE_SIZE);
+	if (IS_ERR(obj)) {
+		err = PTR_ERR(obj);
+		goto put1;
+	}
+
+	i915_gem_ww_ctx_init(&ww, false);
+retry:
+	/* Lock the objects, twice for good measure (-EALREADY handling) */
+	err = i915_gem_object_lock(&ww, obj);
+	if (!err)
+		err = i915_gem_object_lock_interruptible(&ww, obj);
+	if (!err)
+		err = i915_gem_object_lock_interruptible(&ww, obj2);
+	if (!err)
+		err = i915_gem_object_lock(&ww, obj2);
+
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(&ww);
+		if (!err)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
+	i915_gem_object_put(obj2);
+put1:
+	i915_gem_object_put(obj);
+	return err;
+}
+
 int i915_gem_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
 		SUBTEST(igt_gem_suspend),
 		SUBTEST(igt_gem_hibernate),
+		SUBTEST(igt_gem_ww_ctx),
 	};
 
 	if (intel_gt_is_wedged(&i915->gt))
diff --git a/drivers/gpu/drm/i915/selftests/i915_vma.c b/drivers/gpu/drm/i915/selftests/i915_vma.c
index 58b5f40a07dd..24f29f519d33 100644
--- a/drivers/gpu/drm/i915/selftests/i915_vma.c
+++ b/drivers/gpu/drm/i915/selftests/i915_vma.c
@@ -892,7 +892,7 @@  static int igt_vma_remapped_gtt(void *arg)
 			unsigned int x, y;
 			int err;
 
-			i915_gem_object_lock(obj);
+			i915_gem_object_lock(NULL, obj);
 			err = i915_gem_object_set_to_gtt_domain(obj, true);
 			i915_gem_object_unlock(obj);
 			if (err)
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index 04d0aa7b349e..e4de711e107e 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -273,7 +273,7 @@  static int igt_cpu_check(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 	unsigned long n;
 	int err;
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_gem_object_set_to_wc_domain(obj, false);
 	i915_gem_object_unlock(obj);
 	if (err)
@@ -512,7 +512,7 @@  static int igt_lmem_write_cpu(void *arg)
 	if (err)
 		goto out_unpin;
 
-	i915_gem_object_lock(obj);
+	i915_gem_object_lock(NULL, obj);
 	err = i915_gem_object_set_to_wc_domain(obj, true);
 	i915_gem_object_unlock(obj);
 	if (err)