[PATCH 1/2] drm/i915: Remove asynchronous vma binding

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

Commit e3793468b466 ("drm/i915: Use the async worker to avoid reclaim
tainting the ggtt->mutex") moves the vma binding to dma_fence_work,
but dma_fence_work has has signalling fence semantics.

On braswell, we can call stop_machine inside fence_work, causing a splat
because memory allocation inside stop_machine is allowed.

This patch does not fix that lockdep splat yet, but will allow the next
patch to remove it.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/gem/i915_gem_stolen.c |   3 -
 drivers/gpu/drm/i915/gt/gen6_ppgtt.c       |   1 -
 drivers/gpu/drm/i915/gt/gen8_ppgtt.c       |   1 -
 drivers/gpu/drm/i915/gt/intel_ggtt.c       |   4 -
 drivers/gpu/drm/i915/gt/intel_gtt.h        |   2 -
 drivers/gpu/drm/i915/i915_gem.c            |   6 -
 drivers/gpu/drm/i915/i915_vma.c            | 174 +++------------------
 drivers/gpu/drm/i915/i915_vma.h            |   5 +-
 drivers/gpu/drm/i915/i915_vma_types.h      |   3 -
 9 files changed, 21 insertions(+), 178 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
index b0597de206de..ec04df0a3b89 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
@@ -505,9 +505,6 @@ static void dbg_poison(struct i915_ggtt *ggtt,
 	if (!drm_mm_node_allocated(&ggtt->error_capture))
 		return;
 
-	if (ggtt->vm.bind_async_flags & I915_VMA_GLOBAL_BIND)
-		return; /* beware stop_machine() inversion */
-
 	GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
 
 	mutex_lock(&ggtt->error_mutex);
diff --git a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
index e08dff376339..0c5a9a767849 100644
--- a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
@@ -436,7 +436,6 @@ struct i915_ppgtt *gen6_ppgtt_create(struct intel_gt *gt)
 	ppgtt->base.vm.pd_shift = ilog2(SZ_4K * SZ_4K / sizeof(gen6_pte_t));
 	ppgtt->base.vm.top = 1;
 
-	ppgtt->base.vm.bind_async_flags = I915_VMA_LOCAL_BIND;
 	ppgtt->base.vm.allocate_va_range = gen6_alloc_va_range;
 	ppgtt->base.vm.clear_range = gen6_ppgtt_clear_range;
 	ppgtt->base.vm.insert_entries = gen6_ppgtt_insert_entries;
diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
index 176c19633412..92f8a23e66cc 100644
--- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
@@ -736,7 +736,6 @@ struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt)
 			goto err_free_pd;
 	}
 
-	ppgtt->vm.bind_async_flags = I915_VMA_LOCAL_BIND;
 	ppgtt->vm.insert_entries = gen8_ppgtt_insert;
 	ppgtt->vm.allocate_va_range = gen8_ppgtt_alloc;
 	ppgtt->vm.clear_range = gen8_ppgtt_clear;
diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index 670c1271e7d5..e1ec6edae1fb 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -127,7 +127,6 @@ void i915_ggtt_suspend(struct i915_ggtt *ggtt)
 
 	list_for_each_entry_safe(vma, vn, &ggtt->vm.bound_list, vm_link) {
 		GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
-		i915_vma_wait_for_bind(vma);
 
 		if (i915_vma_is_pinned(vma))
 			continue;
@@ -671,7 +670,6 @@ static int init_aliasing_ppgtt(struct i915_ggtt *ggtt)
 	ppgtt->vm.allocate_va_range(&ppgtt->vm, &stash, 0, ggtt->vm.total);
 
 	ggtt->alias = ppgtt;
-	ggtt->vm.bind_async_flags |= ppgtt->vm.bind_async_flags;
 
 	GEM_BUG_ON(ggtt->vm.vma_ops.bind_vma != ggtt_bind_vma);
 	ggtt->vm.vma_ops.bind_vma = aliasing_gtt_bind_vma;
@@ -911,8 +909,6 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
 	    IS_CHERRYVIEW(i915) /* fails with concurrent use/update */) {
 		ggtt->vm.insert_entries = bxt_vtd_ggtt_insert_entries__BKL;
 		ggtt->vm.insert_page    = bxt_vtd_ggtt_insert_page__BKL;
-		ggtt->vm.bind_async_flags =
-			I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND;
 	}
 
 	ggtt->invalidate = gen8_ggtt_invalidate;
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index e67e34e17913..d9d2ca8b4b61 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -230,8 +230,6 @@ struct i915_address_space {
 	u64 total;		/* size addr space maps (ex. 2GB for ggtt) */
 	u64 reserved;		/* size addr space reserved */
 
-	unsigned int bind_async_flags;
-
 	/*
 	 * Each active user context has its own address space (in full-ppgtt).
 	 * Since the vm may be shared between multiple contexts, we count how
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index b23f58e94cfb..4639c47c038b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -946,12 +946,6 @@ i915_gem_object_ggtt_pin_ww(struct drm_i915_gem_object *obj,
 		mutex_unlock(&ggtt->vm.mutex);
 	}
 
-	ret = i915_vma_wait_for_bind(vma);
-	if (ret) {
-		i915_vma_unpin(vma);
-		return ERR_PTR(ret);
-	}
-
 	return vma;
 }
 
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 07490db51cdc..e4b2590d41ce 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -289,79 +289,6 @@ i915_vma_instance(struct drm_i915_gem_object *obj,
 	return vma;
 }
 
-struct i915_vma_work {
-	struct dma_fence_work base;
-	struct i915_address_space *vm;
-	struct i915_vm_pt_stash stash;
-	struct i915_vma *vma;
-	struct drm_i915_gem_object *pinned;
-	struct i915_sw_dma_fence_cb cb;
-	enum i915_cache_level cache_level;
-	unsigned int flags;
-};
-
-static int __vma_bind(struct dma_fence_work *work)
-{
-	struct i915_vma_work *vw = container_of(work, typeof(*vw), base);
-	struct i915_vma *vma = vw->vma;
-
-	vma->ops->bind_vma(vw->vm, &vw->stash,
-			   vma, vw->cache_level, vw->flags);
-	return 0;
-}
-
-static void __vma_release(struct dma_fence_work *work)
-{
-	struct i915_vma_work *vw = container_of(work, typeof(*vw), base);
-
-	if (vw->pinned) {
-		__i915_gem_object_unpin_pages(vw->pinned);
-		i915_gem_object_put(vw->pinned);
-	}
-
-	i915_vm_free_pt_stash(vw->vm, &vw->stash);
-	i915_vm_put(vw->vm);
-}
-
-static const struct dma_fence_work_ops bind_ops = {
-	.name = "bind",
-	.work = __vma_bind,
-	.release = __vma_release,
-};
-
-struct i915_vma_work *i915_vma_work(void)
-{
-	struct i915_vma_work *vw;
-
-	vw = kzalloc(sizeof(*vw), GFP_KERNEL);
-	if (!vw)
-		return NULL;
-
-	dma_fence_work_init(&vw->base, &bind_ops);
-	vw->base.dma.error = -EAGAIN; /* disable the worker by default */
-
-	return vw;
-}
-
-int i915_vma_wait_for_bind(struct i915_vma *vma)
-{
-	int err = 0;
-
-	if (rcu_access_pointer(vma->active.excl.fence)) {
-		struct dma_fence *fence;
-
-		rcu_read_lock();
-		fence = dma_fence_get_rcu_safe(&vma->active.excl.fence);
-		rcu_read_unlock();
-		if (fence) {
-			err = dma_fence_wait(fence, MAX_SCHEDULE_TIMEOUT);
-			dma_fence_put(fence);
-		}
-	}
-
-	return err;
-}
-
 /**
  * i915_vma_bind - Sets up PTEs for an VMA in it's corresponding address space.
  * @vma: VMA to map
@@ -375,8 +302,7 @@ int i915_vma_wait_for_bind(struct i915_vma *vma)
  */
 int i915_vma_bind(struct i915_vma *vma,
 		  enum i915_cache_level cache_level,
-		  u32 flags,
-		  struct i915_vma_work *work)
+		  u32 flags, struct i915_vm_pt_stash *stash)
 {
 	u32 bind_flags;
 	u32 vma_flags;
@@ -405,39 +331,7 @@ int i915_vma_bind(struct i915_vma *vma,
 	GEM_BUG_ON(!vma->pages);
 
 	trace_i915_vma_bind(vma, bind_flags);
-	if (work && bind_flags & vma->vm->bind_async_flags) {
-		struct dma_fence *prev;
-
-		work->vma = vma;
-		work->cache_level = cache_level;
-		work->flags = bind_flags;
-
-		/*
-		 * Note we only want to chain up to the migration fence on
-		 * the pages (not the object itself). As we don't track that,
-		 * yet, we have to use the exclusive fence instead.
-		 *
-		 * Also note that we do not want to track the async vma as
-		 * part of the obj->resv->excl_fence as it only affects
-		 * execution and not content or object's backing store lifetime.
-		 */
-		prev = i915_active_set_exclusive(&vma->active, &work->base.dma);
-		if (prev) {
-			__i915_sw_fence_await_dma_fence(&work->base.chain,
-							prev,
-							&work->cb);
-			dma_fence_put(prev);
-		}
-
-		work->base.dma.error = 0; /* enable the queue_work() */
-
-		if (vma->obj) {
-			__i915_gem_object_pin_pages(vma->obj);
-			work->pinned = i915_gem_object_get(vma->obj);
-		}
-	} else {
-		vma->ops->bind_vma(vma->vm, NULL, vma, cache_level, bind_flags);
-	}
+	vma->ops->bind_vma(vma->vm, stash, vma, cache_level, bind_flags);
 
 	atomic_or(bind_flags, &vma->flags);
 	return 0;
@@ -531,9 +425,6 @@ bool i915_vma_misplaced(const struct i915_vma *vma,
 	if (!drm_mm_node_allocated(&vma->node))
 		return false;
 
-	if (test_bit(I915_VMA_ERROR_BIT, __i915_vma_flags(vma)))
-		return true;
-
 	if (vma->node.size < size)
 		return true;
 
@@ -752,7 +643,7 @@ static bool try_qad_pin(struct i915_vma *vma, unsigned int flags)
 		if (unlikely(flags & ~bound))
 			return false;
 
-		if (unlikely(bound & (I915_VMA_OVERFLOW | I915_VMA_ERROR)))
+		if (unlikely(bound & I915_VMA_OVERFLOW))
 			return false;
 
 		if (!(bound & I915_VMA_PIN_MASK))
@@ -770,7 +661,7 @@ static bool try_qad_pin(struct i915_vma *vma, unsigned int flags)
 	 */
 	mutex_lock(&vma->vm->mutex);
 	do {
-		if (unlikely(bound & (I915_VMA_OVERFLOW | I915_VMA_ERROR))) {
+		if (unlikely(bound & I915_VMA_OVERFLOW)) {
 			pinned = false;
 			break;
 		}
@@ -857,10 +748,10 @@ static void vma_unbind_pages(struct i915_vma *vma)
 int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 		    u64 size, u64 alignment, u64 flags)
 {
-	struct i915_vma_work *work = NULL;
 	intel_wakeref_t wakeref = 0;
 	unsigned int bound;
 	int err;
+	struct i915_vm_pt_stash stash = {};
 
 #ifdef CONFIG_PROVE_LOCKING
 	if (debug_locks && !WARN_ON(!ww) && vma->resv)
@@ -883,33 +774,21 @@ int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 	if (flags & PIN_GLOBAL)
 		wakeref = intel_runtime_pm_get(&vma->vm->i915->runtime_pm);
 
-	if (flags & vma->vm->bind_async_flags) {
-		/* lock VM */
-		err = i915_vm_lock_objects(vma->vm, ww);
+	if (vma->vm->allocate_va_range) {
+		err = i915_vm_alloc_pt_stash(vma->vm,
+					     &stash,
+					     vma->size);
 		if (err)
 			goto err_rpm;
 
-		work = i915_vma_work();
-		if (!work) {
-			err = -ENOMEM;
+		err = i915_vm_lock_objects(vma->vm, ww);
+		if (err)
 			goto err_rpm;
-		}
 
-		work->vm = i915_vm_get(vma->vm);
-
-		/* Allocate enough page directories to used PTE */
-		if (vma->vm->allocate_va_range) {
-			err = i915_vm_alloc_pt_stash(vma->vm,
-						     &work->stash,
-						     vma->size);
-			if (err)
-				goto err_fence;
-
-			err = i915_vm_pin_pt_stash(vma->vm,
-						   &work->stash);
-			if (err)
-				goto err_fence;
-		}
+		err = i915_vm_pin_pt_stash(vma->vm,
+					   &stash);
+		if (err)
+			goto err_rpm;
 	}
 
 	/*
@@ -932,7 +811,7 @@ int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 	err = mutex_lock_interruptible_nested(&vma->vm->mutex,
 					      !(flags & PIN_GLOBAL));
 	if (err)
-		goto err_fence;
+		goto err_rpm;
 
 	/* No more allocations allowed now we hold vm->mutex */
 
@@ -942,11 +821,6 @@ int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 	}
 
 	bound = atomic_read(&vma->flags);
-	if (unlikely(bound & I915_VMA_ERROR)) {
-		err = -ENOMEM;
-		goto err_unlock;
-	}
-
 	if (unlikely(!((bound + 1) & I915_VMA_PIN_MASK))) {
 		err = -EAGAIN; /* pins are meant to be fairly temporary */
 		goto err_unlock;
@@ -973,7 +847,7 @@ int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 	GEM_BUG_ON(!vma->pages);
 	err = i915_vma_bind(vma,
 			    vma->obj ? vma->obj->cache_level : 0,
-			    flags, work);
+			    flags, &stash);
 	if (err)
 		goto err_remove;
 
@@ -996,10 +870,8 @@ int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 	i915_active_release(&vma->active);
 err_unlock:
 	mutex_unlock(&vma->vm->mutex);
-err_fence:
-	if (work)
-		dma_fence_work_commit_imm(&work->base);
 err_rpm:
+	i915_vm_free_pt_stash(vma->vm, &stash);
 	if (wakeref)
 		intel_runtime_pm_put(&vma->vm->i915->runtime_pm, wakeref);
 	vma_put_pages(vma);
@@ -1034,14 +906,8 @@ int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 			err = i915_vma_pin_ww(vma, ww, 0, align, flags | PIN_GLOBAL);
 		else
 			err = i915_vma_pin(vma, 0, align, flags | PIN_GLOBAL);
-		if (err != -ENOSPC) {
-			if (!err) {
-				err = i915_vma_wait_for_bind(vma);
-				if (err)
-					i915_vma_unpin(vma);
-			}
+		if (err != -ENOSPC)
 			return err;
-		}
 
 		/* Unlike i915_vma_pin, we don't take no for an answer! */
 		flush_idle_contexts(vm->gt);
@@ -1306,7 +1172,7 @@ void __i915_vma_evict(struct i915_vma *vma)
 		trace_i915_vma_unbind(vma);
 		vma->ops->unbind_vma(vma->vm, vma);
 	}
-	atomic_and(~(I915_VMA_BIND_MASK | I915_VMA_ERROR | I915_VMA_GGTT_WRITE),
+	atomic_and(~(I915_VMA_BIND_MASK | I915_VMA_GGTT_WRITE),
 		   &vma->flags);
 
 	i915_vma_detach(vma);
diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
index 8df784a026d2..d1d0fc76ef99 100644
--- a/drivers/gpu/drm/i915/i915_vma.h
+++ b/drivers/gpu/drm/i915/i915_vma.h
@@ -195,11 +195,10 @@ i915_vma_compare(struct i915_vma *vma,
 	return memcmp(&vma->ggtt_view.partial, &view->partial, view->type);
 }
 
-struct i915_vma_work *i915_vma_work(void);
 int i915_vma_bind(struct i915_vma *vma,
 		  enum i915_cache_level cache_level,
 		  u32 flags,
-		  struct i915_vma_work *work);
+		  struct i915_vm_pt_stash *stash);
 
 bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long color);
 bool i915_vma_misplaced(const struct i915_vma *vma,
@@ -418,8 +417,6 @@ struct i915_vma *i915_vma_make_unshrinkable(struct i915_vma *vma);
 void i915_vma_make_shrinkable(struct i915_vma *vma);
 void i915_vma_make_purgeable(struct i915_vma *vma);
 
-int i915_vma_wait_for_bind(struct i915_vma *vma);
-
 static inline int i915_vma_sync(struct i915_vma *vma)
 {
 	/* Wait for the asynchronous bindings and pending GPU reads */
diff --git a/drivers/gpu/drm/i915/i915_vma_types.h b/drivers/gpu/drm/i915/i915_vma_types.h
index 6b1bfa230b82..82868a755a96 100644
--- a/drivers/gpu/drm/i915/i915_vma_types.h
+++ b/drivers/gpu/drm/i915/i915_vma_types.h
@@ -240,9 +240,6 @@ struct i915_vma {
 
 #define I915_VMA_ALLOC_BIT	12
 
-#define I915_VMA_ERROR_BIT	13
-#define I915_VMA_ERROR		((int)BIT(I915_VMA_ERROR_BIT))
-
 #define I915_VMA_GGTT_BIT	14
 #define I915_VMA_CAN_FENCE_BIT	15
 #define I915_VMA_USERFAULT_BIT	16
-- 
2.31.0

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