1 files changed, 329 insertions, 642 deletions

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index c31a6744daee..77cc3af3d518 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -1,727 +1,428 @@
+// SPDX-License-Identifier: MIT
 /*
- * SPDX-License-Identifier: MIT
- *
  * Copyright © 2012-2014 Intel Corporation
+ *
+ * Based on amdgpu_mn, which bears the following notice:
+ *
+ * Copyright 2014 Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ */
+/*
+ * Authors:
+ *    Christian König <christian.koenig@amd.com>
  */
 
 #include <linux/mmu_context.h>
-#include <linux/mmu_notifier.h>
 #include <linux/mempolicy.h>
 #include <linux/swap.h>
 #include <linux/sched/mm.h>
 
+#include <drm/drm_print.h>
+
 #include "i915_drv.h"
 #include "i915_gem_ioctls.h"
 #include "i915_gem_object.h"
 #include "i915_scatterlist.h"
 
-struct i915_mm_struct {
-	struct mm_struct *mm;
-	struct drm_i915_private *i915;
-	struct i915_mmu_notifier *mn;
-	struct hlist_node node;
-	struct kref kref;
-	struct work_struct work;
-};
-
-#if defined(CONFIG_MMU_NOTIFIER)
-#include <linux/interval_tree.h>
-
-struct i915_mmu_notifier {
-	spinlock_t lock;
-	struct hlist_node node;
-	struct mmu_notifier mn;
-	struct rb_root_cached objects;
-	struct i915_mm_struct *mm;
-};
-
-struct i915_mmu_object {
-	struct i915_mmu_notifier *mn;
-	struct drm_i915_gem_object *obj;
-	struct interval_tree_node it;
-};
-
-static void add_object(struct i915_mmu_object *mo)
-{
-	GEM_BUG_ON(!RB_EMPTY_NODE(&mo->it.rb));
-	interval_tree_insert(&mo->it, &mo->mn->objects);
-}
-
-static void del_object(struct i915_mmu_object *mo)
-{
-	if (RB_EMPTY_NODE(&mo->it.rb))
-		return;
-
-	interval_tree_remove(&mo->it, &mo->mn->objects);
-	RB_CLEAR_NODE(&mo->it.rb);
-}
+#ifdef CONFIG_MMU_NOTIFIER
 
-static void
-__i915_gem_userptr_set_active(struct drm_i915_gem_object *obj, bool value)
+/**
+ * i915_gem_userptr_invalidate - callback to notify about mm change
+ *
+ * @mni: the range (mm) is about to update
+ * @range: details on the invalidation
+ * @cur_seq: Value to pass to mmu_interval_set_seq()
+ *
+ * Block for operations on BOs to finish and mark pages as accessed and
+ * potentially dirty.
+ */
+static bool i915_gem_userptr_invalidate(struct mmu_interval_notifier *mni,
+					const struct mmu_notifier_range *range,
+					unsigned long cur_seq)
 {
-	struct i915_mmu_object *mo = obj->userptr.mmu_object;
-
-	/*
-	 * During mm_invalidate_range we need to cancel any userptr that
-	 * overlaps the range being invalidated. Doing so requires the
-	 * struct_mutex, and that risks recursion. In order to cause
-	 * recursion, the user must alias the userptr address space with
-	 * a GTT mmapping (possible with a MAP_FIXED) - then when we have
-	 * to invalidate that mmaping, mm_invalidate_range is called with
-	 * the userptr address *and* the struct_mutex held.  To prevent that
-	 * we set a flag under the i915_mmu_notifier spinlock to indicate
-	 * whether this object is valid.
-	 */
-	if (!mo)
-		return;
-
-	spin_lock(&mo->mn->lock);
-	if (value)
-		add_object(mo);
-	else
-		del_object(mo);
-	spin_unlock(&mo->mn->lock);
+	mmu_interval_set_seq(mni, cur_seq);
+	return true;
 }
 
-static int
-userptr_mn_invalidate_range_start(struct mmu_notifier *_mn,
-				  const struct mmu_notifier_range *range)
-{
-	struct i915_mmu_notifier *mn =
-		container_of(_mn, struct i915_mmu_notifier, mn);
-	struct interval_tree_node *it;
-	unsigned long end;
-	int ret = 0;
-
-	if (RB_EMPTY_ROOT(&mn->objects.rb_root))
-		return 0;
-
-	/* interval ranges are inclusive, but invalidate range is exclusive */
-	end = range->end - 1;
-
-	spin_lock(&mn->lock);
-	it = interval_tree_iter_first(&mn->objects, range->start, end);
-	while (it) {
-		struct drm_i915_gem_object *obj;
-
-		if (!mmu_notifier_range_blockable(range)) {
-			ret = -EAGAIN;
-			break;
-		}
-
-		/*
-		 * The mmu_object is released late when destroying the
-		 * GEM object so it is entirely possible to gain a
-		 * reference on an object in the process of being freed
-		 * since our serialisation is via the spinlock and not
-		 * the struct_mutex - and consequently use it after it
-		 * is freed and then double free it. To prevent that
-		 * use-after-free we only acquire a reference on the
-		 * object if it is not in the process of being destroyed.
-		 */
-		obj = container_of(it, struct i915_mmu_object, it)->obj;
-		if (!kref_get_unless_zero(&obj->base.refcount)) {
-			it = interval_tree_iter_next(it, range->start, end);
-			continue;
-		}
-		spin_unlock(&mn->lock);
-
-		ret = i915_gem_object_unbind(obj,
-					     I915_GEM_OBJECT_UNBIND_ACTIVE |
-					     I915_GEM_OBJECT_UNBIND_BARRIER);
-		if (ret == 0)
-			ret = __i915_gem_object_put_pages(obj);
-		i915_gem_object_put(obj);
-		if (ret)
-			return ret;
-
-		spin_lock(&mn->lock);
-
-		/*
-		 * As we do not (yet) protect the mmu from concurrent insertion
-		 * over this range, there is no guarantee that this search will
-		 * terminate given a pathologic workload.
-		 */
-		it = interval_tree_iter_first(&mn->objects, range->start, end);
-	}
-	spin_unlock(&mn->lock);
-
-	return ret;
-
-}
-
-static const struct mmu_notifier_ops i915_gem_userptr_notifier = {
-	.invalidate_range_start = userptr_mn_invalidate_range_start,
+static const struct mmu_interval_notifier_ops i915_gem_userptr_notifier_ops = {
+	.invalidate = i915_gem_userptr_invalidate,
 };
 
-static struct i915_mmu_notifier *
-i915_mmu_notifier_create(struct i915_mm_struct *mm)
+static int
+i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj)
 {
-	struct i915_mmu_notifier *mn;
-
-	mn = kmalloc(sizeof(*mn), GFP_KERNEL);
-	if (mn == NULL)
-		return ERR_PTR(-ENOMEM);
-
-	spin_lock_init(&mn->lock);
-	mn->mn.ops = &i915_gem_userptr_notifier;
-	mn->objects = RB_ROOT_CACHED;
-	mn->mm = mm;
-
-	return mn;
+	return mmu_interval_notifier_insert(&obj->userptr.notifier, current->mm,
+					    obj->userptr.ptr, obj->base.size,
+					    &i915_gem_userptr_notifier_ops);
 }
 
-static void
-i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj)
+static void i915_gem_object_userptr_drop_ref(struct drm_i915_gem_object *obj)
 {
-	struct i915_mmu_object *mo;
+	struct page **pvec = NULL;
 
-	mo = fetch_and_zero(&obj->userptr.mmu_object);
-	if (!mo)
-		return;
-
-	spin_lock(&mo->mn->lock);
-	del_object(mo);
-	spin_unlock(&mo->mn->lock);
-	kfree(mo);
-}
+	assert_object_held_shared(obj);
 
-static struct i915_mmu_notifier *
-i915_mmu_notifier_find(struct i915_mm_struct *mm)
-{
-	struct i915_mmu_notifier *mn;
-	int err = 0;
-
-	mn = mm->mn;
-	if (mn)
-		return mn;
-
-	mn = i915_mmu_notifier_create(mm);
-	if (IS_ERR(mn))
-		err = PTR_ERR(mn);
-
-	mmap_write_lock(mm->mm);
-	mutex_lock(&mm->i915->mm_lock);
-	if (mm->mn == NULL && !err) {
-		/* Protected by mmap_lock (write-lock) */
-		err = __mmu_notifier_register(&mn->mn, mm->mm);
-		if (!err) {
-			/* Protected by mm_lock */
-			mm->mn = fetch_and_zero(&mn);
-		}
-	} else if (mm->mn) {
-		/*
-		 * Someone else raced and successfully installed the mmu
-		 * notifier, we can cancel our own errors.
-		 */
-		err = 0;
+	if (!--obj->userptr.page_ref) {
+		pvec = obj->userptr.pvec;
+		obj->userptr.pvec = NULL;
 	}
-	mutex_unlock(&mm->i915->mm_lock);
-	mmap_write_unlock(mm->mm);
+	GEM_BUG_ON(obj->userptr.page_ref < 0);
 
-	if (mn && !IS_ERR(mn))
-		kfree(mn);
+	if (pvec) {
+		const unsigned long num_pages = obj->base.size >> PAGE_SHIFT;
 
-	return err ? ERR_PTR(err) : mm->mn;
+		unpin_user_pages(pvec, num_pages);
+		kvfree(pvec);
+	}
 }
 
-static int
-i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj,
-				    unsigned flags)
+static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 {
-	struct i915_mmu_notifier *mn;
-	struct i915_mmu_object *mo;
-
-	if (flags & I915_USERPTR_UNSYNCHRONIZED)
-		return capable(CAP_SYS_ADMIN) ? 0 : -EPERM;
-
-	if (WARN_ON(obj->userptr.mm == NULL))
-		return -EINVAL;
+	unsigned int max_segment = i915_sg_segment_size(obj->base.dev->dev);
+	struct sg_table *st;
+	struct page **pvec;
+	unsigned int num_pages; /* limited by sg_alloc_table_from_pages_segment */
+	int ret;
 
-	mn = i915_mmu_notifier_find(obj->userptr.mm);
-	if (IS_ERR(mn))
-		return PTR_ERR(mn);
+	if (overflows_type(obj->base.size >> PAGE_SHIFT, num_pages))
+		return -E2BIG;
 
-	mo = kzalloc(sizeof(*mo), GFP_KERNEL);
-	if (!mo)
+	num_pages = obj->base.size >> PAGE_SHIFT;
+	st = kmalloc(sizeof(*st), GFP_KERNEL);
+	if (!st)
 		return -ENOMEM;
 
-	mo->mn = mn;
-	mo->obj = obj;
-	mo->it.start = obj->userptr.ptr;
-	mo->it.last = obj->userptr.ptr + obj->base.size - 1;
-	RB_CLEAR_NODE(&mo->it.rb);
-
-	obj->userptr.mmu_object = mo;
-	return 0;
-}
+	if (!obj->userptr.page_ref) {
+		ret = -EAGAIN;
+		goto err_free;
+	}
 
-static void
-i915_mmu_notifier_free(struct i915_mmu_notifier *mn,
-		       struct mm_struct *mm)
-{
-	if (mn == NULL)
-		return;
+	obj->userptr.page_ref++;
+	pvec = obj->userptr.pvec;
 
-	mmu_notifier_unregister(&mn->mn, mm);
-	kfree(mn);
-}
+alloc_table:
+	ret = sg_alloc_table_from_pages_segment(st, pvec, num_pages, 0,
+						num_pages << PAGE_SHIFT,
+						max_segment, GFP_KERNEL);
+	if (ret)
+		goto err;
 
-#else
+	ret = i915_gem_gtt_prepare_pages(obj, st);
+	if (ret) {
+		sg_free_table(st);
 
-static void
-__i915_gem_userptr_set_active(struct drm_i915_gem_object *obj, bool value)
-{
-}
+		if (max_segment > PAGE_SIZE) {
+			max_segment = PAGE_SIZE;
+			goto alloc_table;
+		}
 
-static void
-i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj)
-{
-}
+		goto err;
+	}
 
-static int
-i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj,
-				    unsigned flags)
-{
-	if ((flags & I915_USERPTR_UNSYNCHRONIZED) == 0)
-		return -ENODEV;
+	WARN_ON_ONCE(!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE));
+	if (i915_gem_object_can_bypass_llc(obj))
+		obj->cache_dirty = true;
 
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
+	__i915_gem_object_set_pages(obj, st);
 
 	return 0;
-}
 
-static void
-i915_mmu_notifier_free(struct i915_mmu_notifier *mn,
-		       struct mm_struct *mm)
-{
+err:
+	i915_gem_object_userptr_drop_ref(obj);
+err_free:
+	kfree(st);
+	return ret;
 }
 
-#endif
-
-static struct i915_mm_struct *
-__i915_mm_struct_find(struct drm_i915_private *dev_priv, struct mm_struct *real)
+static void
+i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
+			   struct sg_table *pages)
 {
-	struct i915_mm_struct *mm;
+	struct sgt_iter sgt_iter;
+	struct page *page;
 
-	/* Protected by dev_priv->mm_lock */
-	hash_for_each_possible(dev_priv->mm_structs, mm, node, (unsigned long)real)
-		if (mm->mm == real)
-			return mm;
+	if (!pages)
+		return;
 
-	return NULL;
-}
+	__i915_gem_object_release_shmem(obj, pages, true);
+	i915_gem_gtt_finish_pages(obj, pages);
 
-static int
-i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj)
-{
-	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
-	struct i915_mm_struct *mm;
-	int ret = 0;
-
-	/* During release of the GEM object we hold the struct_mutex. This
-	 * precludes us from calling mmput() at that time as that may be
-	 * the last reference and so call exit_mmap(). exit_mmap() will
-	 * attempt to reap the vma, and if we were holding a GTT mmap
-	 * would then call drm_gem_vm_close() and attempt to reacquire
-	 * the struct mutex. So in order to avoid that recursion, we have
-	 * to defer releasing the mm reference until after we drop the
-	 * struct_mutex, i.e. we need to schedule a worker to do the clean
-	 * up.
+	/*
+	 * We always mark objects as dirty when they are used by the GPU,
+	 * just in case. However, if we set the vma as being read-only we know
+	 * that the object will never have been written to.
 	 */
-	mutex_lock(&dev_priv->mm_lock);
-	mm = __i915_mm_struct_find(dev_priv, current->mm);
-	if (mm == NULL) {
-		mm = kmalloc(sizeof(*mm), GFP_KERNEL);
-		if (mm == NULL) {
-			ret = -ENOMEM;
-			goto out;
-		}
-
-		kref_init(&mm->kref);
-		mm->i915 = to_i915(obj->base.dev);
+	if (i915_gem_object_is_readonly(obj))
+		obj->mm.dirty = false;
 
-		mm->mm = current->mm;
-		mmgrab(current->mm);
+	for_each_sgt_page(page, sgt_iter, pages) {
+		if (obj->mm.dirty && trylock_page(page)) {
+			/*
+			 * As this may not be anonymous memory (e.g. shmem)
+			 * but exist on a real mapping, we have to lock
+			 * the page in order to dirty it -- holding
+			 * the page reference is not sufficient to
+			 * prevent the inode from being truncated.
+			 * Play safe and take the lock.
+			 *
+			 * However...!
+			 *
+			 * The mmu-notifier can be invalidated for a
+			 * migrate_folio, that is alreadying holding the lock
+			 * on the folio. Such a try_to_unmap() will result
+			 * in us calling put_pages() and so recursively try
+			 * to lock the page. We avoid that deadlock with
+			 * a trylock_page() and in exchange we risk missing
+			 * some page dirtying.
+			 */
+			set_page_dirty(page);
+			unlock_page(page);
+		}
 
-		mm->mn = NULL;
+		mark_page_accessed(page);
+	}
+	obj->mm.dirty = false;
 
-		/* Protected by dev_priv->mm_lock */
-		hash_add(dev_priv->mm_structs,
-			 &mm->node, (unsigned long)mm->mm);
-	} else
-		kref_get(&mm->kref);
+	sg_free_table(pages);
+	kfree(pages);
 
-	obj->userptr.mm = mm;
-out:
-	mutex_unlock(&dev_priv->mm_lock);
-	return ret;
+	i915_gem_object_userptr_drop_ref(obj);
 }
 
-static void
-__i915_mm_struct_free__worker(struct work_struct *work)
+static int i915_gem_object_userptr_unbind(struct drm_i915_gem_object *obj)
 {
-	struct i915_mm_struct *mm = container_of(work, typeof(*mm), work);
-	i915_mmu_notifier_free(mm->mn, mm->mm);
-	mmdrop(mm->mm);
-	kfree(mm);
-}
+	struct sg_table *pages;
+	int err;
 
-static void
-__i915_mm_struct_free(struct kref *kref)
-{
-	struct i915_mm_struct *mm = container_of(kref, typeof(*mm), kref);
+	err = i915_gem_object_unbind(obj, I915_GEM_OBJECT_UNBIND_ACTIVE);
+	if (err)
+		return err;
 
-	/* Protected by dev_priv->mm_lock */
-	hash_del(&mm->node);
-	mutex_unlock(&mm->i915->mm_lock);
+	if (GEM_WARN_ON(i915_gem_object_has_pinned_pages(obj)))
+		return -EBUSY;
 
-	INIT_WORK(&mm->work, __i915_mm_struct_free__worker);
-	queue_work(mm->i915->mm.userptr_wq, &mm->work);
-}
+	assert_object_held(obj);
 
-static void
-i915_gem_userptr_release__mm_struct(struct drm_i915_gem_object *obj)
-{
-	if (obj->userptr.mm == NULL)
-		return;
+	pages = __i915_gem_object_unset_pages(obj);
+	if (!IS_ERR_OR_NULL(pages))
+		i915_gem_userptr_put_pages(obj, pages);
 
-	kref_put_mutex(&obj->userptr.mm->kref,
-		       __i915_mm_struct_free,
-		       &to_i915(obj->base.dev)->mm_lock);
-	obj->userptr.mm = NULL;
+	return err;
 }
 
-struct get_pages_work {
-	struct work_struct work;
-	struct drm_i915_gem_object *obj;
-	struct task_struct *task;
-};
-
-static struct sg_table *
-__i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj,
-			       struct page **pvec, unsigned long num_pages)
+int i915_gem_object_userptr_submit_init(struct drm_i915_gem_object *obj)
 {
-	unsigned int max_segment = i915_sg_segment_size();
-	struct sg_table *st;
-	unsigned int sg_page_sizes;
-	int ret;
-
-	st = kmalloc(sizeof(*st), GFP_KERNEL);
-	if (!st)
-		return ERR_PTR(-ENOMEM);
+	const unsigned long num_pages = obj->base.size >> PAGE_SHIFT;
+	struct page **pvec;
+	unsigned int gup_flags = 0;
+	unsigned long notifier_seq;
+	int pinned, ret;
 
-alloc_table:
-	ret = __sg_alloc_table_from_pages(st, pvec, num_pages,
-					  0, num_pages << PAGE_SHIFT,
-					  max_segment,
-					  GFP_KERNEL);
-	if (ret) {
-		kfree(st);
-		return ERR_PTR(ret);
-	}
+	if (obj->userptr.notifier.mm != current->mm)
+		return -EFAULT;
 
-	ret = i915_gem_gtt_prepare_pages(obj, st);
-	if (ret) {
-		sg_free_table(st);
+	notifier_seq = mmu_interval_read_begin(&obj->userptr.notifier);
 
-		if (max_segment > PAGE_SIZE) {
-			max_segment = PAGE_SIZE;
-			goto alloc_table;
-		}
+	ret = i915_gem_object_lock_interruptible(obj, NULL);
+	if (ret)
+		return ret;
 
-		kfree(st);
-		return ERR_PTR(ret);
+	if (notifier_seq == obj->userptr.notifier_seq && obj->userptr.pvec) {
+		i915_gem_object_unlock(obj);
+		return 0;
 	}
 
-	sg_page_sizes = i915_sg_page_sizes(st->sgl);
-
-	__i915_gem_object_set_pages(obj, st, sg_page_sizes);
+	ret = i915_gem_object_userptr_unbind(obj);
+	i915_gem_object_unlock(obj);
+	if (ret)
+		return ret;
 
-	return st;
-}
+	pvec = kvmalloc_array(num_pages, sizeof(struct page *), GFP_KERNEL);
+	if (!pvec)
+		return -ENOMEM;
 
-static void
-__i915_gem_userptr_get_pages_worker(struct work_struct *_work)
-{
-	struct get_pages_work *work = container_of(_work, typeof(*work), work);
-	struct drm_i915_gem_object *obj = work->obj;
-	const unsigned long npages = obj->base.size >> PAGE_SHIFT;
-	unsigned long pinned;
-	struct page **pvec;
-	int ret;
+	if (!i915_gem_object_is_readonly(obj))
+		gup_flags |= FOLL_WRITE;
 
-	ret = -ENOMEM;
 	pinned = 0;
+	while (pinned < num_pages) {
+		ret = pin_user_pages_fast(obj->userptr.ptr + pinned * PAGE_SIZE,
+					  num_pages - pinned, gup_flags,
+					  &pvec[pinned]);
+		if (ret < 0)
+			goto out;
 
-	pvec = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
-	if (pvec != NULL) {
-		struct mm_struct *mm = obj->userptr.mm->mm;
-		unsigned int flags = 0;
-		int locked = 0;
-
-		if (!i915_gem_object_is_readonly(obj))
-			flags |= FOLL_WRITE;
-
-		ret = -EFAULT;
-		if (mmget_not_zero(mm)) {
-			while (pinned < npages) {
-				if (!locked) {
-					mmap_read_lock(mm);
-					locked = 1;
-				}
-				ret = pin_user_pages_remote
-					(work->task, mm,
-					 obj->userptr.ptr + pinned * PAGE_SIZE,
-					 npages - pinned,
-					 flags,
-					 pvec + pinned, NULL, &locked);
-				if (ret < 0)
-					break;
-
-				pinned += ret;
-			}
-			if (locked)
-				mmap_read_unlock(mm);
-			mmput(mm);
-		}
+		pinned += ret;
 	}
 
-	mutex_lock_nested(&obj->mm.lock, I915_MM_GET_PAGES);
-	if (obj->userptr.work == &work->work) {
-		struct sg_table *pages = ERR_PTR(ret);
-
-		if (pinned == npages) {
-			pages = __i915_gem_userptr_alloc_pages(obj, pvec,
-							       npages);
-			if (!IS_ERR(pages)) {
-				pinned = 0;
-				pages = NULL;
-			}
-		}
+	ret = i915_gem_object_lock_interruptible(obj, NULL);
+	if (ret)
+		goto out;
 
-		obj->userptr.work = ERR_CAST(pages);
-		if (IS_ERR(pages))
-			__i915_gem_userptr_set_active(obj, false);
+	if (mmu_interval_read_retry(&obj->userptr.notifier,
+		!obj->userptr.page_ref ? notifier_seq :
+		obj->userptr.notifier_seq)) {
+		ret = -EAGAIN;
+		goto out_unlock;
 	}
-	mutex_unlock(&obj->mm.lock);
 
-	unpin_user_pages(pvec, pinned);
-	kvfree(pvec);
+	if (!obj->userptr.page_ref++) {
+		obj->userptr.pvec = pvec;
+		obj->userptr.notifier_seq = notifier_seq;
+		pvec = NULL;
+		ret = ____i915_gem_object_get_pages(obj);
+	}
 
-	i915_gem_object_put(obj);
-	put_task_struct(work->task);
-	kfree(work);
-}
+	obj->userptr.page_ref--;
 
-static struct sg_table *
-__i915_gem_userptr_get_pages_schedule(struct drm_i915_gem_object *obj)
-{
-	struct get_pages_work *work;
-
-	/* Spawn a worker so that we can acquire the
-	 * user pages without holding our mutex. Access
-	 * to the user pages requires mmap_lock, and we have
-	 * a strict lock ordering of mmap_lock, struct_mutex -
-	 * we already hold struct_mutex here and so cannot
-	 * call gup without encountering a lock inversion.
-	 *
-	 * Userspace will keep on repeating the operation
-	 * (thanks to EAGAIN) until either we hit the fast
-	 * path or the worker completes. If the worker is
-	 * cancelled or superseded, the task is still run
-	 * but the results ignored. (This leads to
-	 * complications that we may have a stray object
-	 * refcount that we need to be wary of when
-	 * checking for existing objects during creation.)
-	 * If the worker encounters an error, it reports
-	 * that error back to this function through
-	 * obj->userptr.work = ERR_PTR.
-	 */
-	work = kmalloc(sizeof(*work), GFP_KERNEL);
-	if (work == NULL)
-		return ERR_PTR(-ENOMEM);
+out_unlock:
+	i915_gem_object_unlock(obj);
 
-	obj->userptr.work = &work->work;
+out:
+	if (pvec) {
+		unpin_user_pages(pvec, pinned);
+		kvfree(pvec);
+	}
 
-	work->obj = i915_gem_object_get(obj);
+	return ret;
+}
 
-	work->task = current;
-	get_task_struct(work->task);
+int i915_gem_object_userptr_submit_done(struct drm_i915_gem_object *obj)
+{
+	if (mmu_interval_read_retry(&obj->userptr.notifier,
+				    obj->userptr.notifier_seq)) {
+		/* We collided with the mmu notifier, need to retry */
 
-	INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker);
-	queue_work(to_i915(obj->base.dev)->mm.userptr_wq, &work->work);
+		return -EAGAIN;
+	}
 
-	return ERR_PTR(-EAGAIN);
+	return 0;
 }
 
-static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
+int i915_gem_object_userptr_validate(struct drm_i915_gem_object *obj)
 {
-	const unsigned long num_pages = obj->base.size >> PAGE_SHIFT;
-	struct mm_struct *mm = obj->userptr.mm->mm;
-	struct page **pvec;
-	struct sg_table *pages;
-	bool active;
-	int pinned;
-	unsigned int gup_flags = 0;
-
-	/* If userspace should engineer that these pages are replaced in
-	 * the vma between us binding this page into the GTT and completion
-	 * of rendering... Their loss. If they change the mapping of their
-	 * pages they need to create a new bo to point to the new vma.
-	 *
-	 * However, that still leaves open the possibility of the vma
-	 * being copied upon fork. Which falls under the same userspace
-	 * synchronisation issue as a regular bo, except that this time
-	 * the process may not be expecting that a particular piece of
-	 * memory is tied to the GPU.
-	 *
-	 * Fortunately, we can hook into the mmu_notifier in order to
-	 * discard the page references prior to anything nasty happening
-	 * to the vma (discard or cloning) which should prevent the more
-	 * egregious cases from causing harm.
-	 */
-
-	if (obj->userptr.work) {
-		/* active flag should still be held for the pending work */
-		if (IS_ERR(obj->userptr.work))
-			return PTR_ERR(obj->userptr.work);
-		else
-			return -EAGAIN;
-	}
+	int err;
 
-	pvec = NULL;
-	pinned = 0;
+	err = i915_gem_object_userptr_submit_init(obj);
+	if (err)
+		return err;
 
-	if (mm == current->mm) {
-		pvec = kvmalloc_array(num_pages, sizeof(struct page *),
-				      GFP_KERNEL |
-				      __GFP_NORETRY |
-				      __GFP_NOWARN);
+	err = i915_gem_object_lock_interruptible(obj, NULL);
+	if (!err) {
 		/*
-		 * Using __get_user_pages_fast() with a read-only
-		 * access is questionable. A read-only page may be
-		 * COW-broken, and then this might end up giving
-		 * the wrong side of the COW..
-		 *
-		 * We may or may not care.
+		 * Since we only check validity, not use the pages,
+		 * it doesn't matter if we collide with the mmu notifier,
+		 * and -EAGAIN handling is not required.
 		 */
-		if (pvec) {
-			/* defer to worker if malloc fails */
-			if (!i915_gem_object_is_readonly(obj))
-				gup_flags |= FOLL_WRITE;
-			pinned = pin_user_pages_fast_only(obj->userptr.ptr,
-							  num_pages, gup_flags,
-							  pvec);
-		}
-	}
+		err = i915_gem_object_pin_pages(obj);
+		if (!err)
+			i915_gem_object_unpin_pages(obj);
 
-	active = false;
-	if (pinned < 0) {
-		pages = ERR_PTR(pinned);
-		pinned = 0;
-	} else if (pinned < num_pages) {
-		pages = __i915_gem_userptr_get_pages_schedule(obj);
-		active = pages == ERR_PTR(-EAGAIN);
-	} else {
-		pages = __i915_gem_userptr_alloc_pages(obj, pvec, num_pages);
-		active = !IS_ERR(pages);
+		i915_gem_object_unlock(obj);
 	}
-	if (active)
-		__i915_gem_userptr_set_active(obj, true);
-
-	if (IS_ERR(pages))
-		unpin_user_pages(pvec, pinned);
-	kvfree(pvec);
 
-	return PTR_ERR_OR_ZERO(pages);
+	return err;
 }
 
 static void
-i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
-			   struct sg_table *pages)
+i915_gem_userptr_release(struct drm_i915_gem_object *obj)
 {
-	struct sgt_iter sgt_iter;
-	struct page *page;
+	GEM_WARN_ON(obj->userptr.page_ref);
 
-	/* Cancel any inflight work and force them to restart their gup */
-	obj->userptr.work = NULL;
-	__i915_gem_userptr_set_active(obj, false);
-	if (!pages)
+	if (!obj->userptr.notifier.mm)
 		return;
 
-	__i915_gem_object_release_shmem(obj, pages, true);
-	i915_gem_gtt_finish_pages(obj, pages);
-
-	/*
-	 * We always mark objects as dirty when they are used by the GPU,
-	 * just in case. However, if we set the vma as being read-only we know
-	 * that the object will never have been written to.
-	 */
-	if (i915_gem_object_is_readonly(obj))
-		obj->mm.dirty = false;
-
-	for_each_sgt_page(page, sgt_iter, pages) {
-		if (obj->mm.dirty && trylock_page(page)) {
-			/*
-			 * As this may not be anonymous memory (e.g. shmem)
-			 * but exist on a real mapping, we have to lock
-			 * the page in order to dirty it -- holding
-			 * the page reference is not sufficient to
-			 * prevent the inode from being truncated.
-			 * Play safe and take the lock.
-			 *
-			 * However...!
-			 *
-			 * The mmu-notifier can be invalidated for a
-			 * migrate_page, that is alreadying holding the lock
-			 * on the page. Such a try_to_unmap() will result
-			 * in us calling put_pages() and so recursively try
-			 * to lock the page. We avoid that deadlock with
-			 * a trylock_page() and in exchange we risk missing
-			 * some page dirtying.
-			 */
-			set_page_dirty(page);
-			unlock_page(page);
-		}
+	mmu_interval_notifier_remove(&obj->userptr.notifier);
+	obj->userptr.notifier.mm = NULL;
+}
 
-		mark_page_accessed(page);
-		unpin_user_page(page);
-	}
-	obj->mm.dirty = false;
+static int
+i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj)
+{
+	drm_dbg(obj->base.dev, "Exporting userptr no longer allowed\n");
 
-	sg_free_table(pages);
-	kfree(pages);
+	return -EINVAL;
 }
 
-static void
-i915_gem_userptr_release(struct drm_i915_gem_object *obj)
+static int
+i915_gem_userptr_pwrite(struct drm_i915_gem_object *obj,
+			const struct drm_i915_gem_pwrite *args)
 {
-	i915_gem_userptr_release__mmu_notifier(obj);
-	i915_gem_userptr_release__mm_struct(obj);
+	drm_dbg(obj->base.dev, "pwrite to userptr no longer allowed\n");
+
+	return -EINVAL;
 }
 
 static int
-i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj)
+i915_gem_userptr_pread(struct drm_i915_gem_object *obj,
+		       const struct drm_i915_gem_pread *args)
 {
-	if (obj->userptr.mmu_object)
-		return 0;
+	drm_dbg(obj->base.dev, "pread from userptr no longer allowed\n");
 
-	return i915_gem_userptr_init__mmu_notifier(obj, 0);
+	return -EINVAL;
 }
 
 static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
-	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
-		 I915_GEM_OBJECT_IS_SHRINKABLE |
+	.name = "i915_gem_object_userptr",
+	.flags = I915_GEM_OBJECT_IS_SHRINKABLE |
 		 I915_GEM_OBJECT_NO_MMAP |
-		 I915_GEM_OBJECT_ASYNC_CANCEL,
+		 I915_GEM_OBJECT_IS_PROXY,
 	.get_pages = i915_gem_userptr_get_pages,
 	.put_pages = i915_gem_userptr_put_pages,
 	.dmabuf_export = i915_gem_userptr_dmabuf_export,
+	.pwrite = i915_gem_userptr_pwrite,
+	.pread = i915_gem_userptr_pread,
 	.release = i915_gem_userptr_release,
 };
 
+#endif
+
+static int
+probe_range(struct mm_struct *mm, unsigned long addr, unsigned long len)
+{
+	VMA_ITERATOR(vmi, mm, addr);
+	struct vm_area_struct *vma;
+	unsigned long end = addr + len;
+
+	mmap_read_lock(mm);
+	for_each_vma_range(vmi, vma, end) {
+		/* Check for holes, note that we also update the addr below */
+		if (vma->vm_start > addr)
+			break;
+
+		if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
+			break;
+
+		addr = vma->vm_end;
+	}
+	mmap_read_unlock(mm);
+
+	if (vma || addr < end)
+		return -EFAULT;
+	return 0;
+}
+
 /*
  * Creates a new mm object that wraps some normal memory from the process
  * context - user memory.
@@ -762,14 +463,14 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
 		       void *data,
 		       struct drm_file *file)
 {
-	static struct lock_class_key lock_class;
-	struct drm_i915_private *dev_priv = to_i915(dev);
+	static struct lock_class_key __maybe_unused lock_class;
+	struct drm_i915_private *i915 = to_i915(dev);
 	struct drm_i915_gem_userptr *args = data;
-	struct drm_i915_gem_object *obj;
-	int ret;
-	u32 handle;
+	struct drm_i915_gem_object __maybe_unused *obj;
+	int __maybe_unused ret;
+	u32 __maybe_unused handle;
 
-	if (!HAS_LLC(dev_priv) && !HAS_SNOOP(dev_priv)) {
+	if (!HAS_LLC(i915) && !HAS_SNOOP(i915)) {
 		/* We cannot support coherent userptr objects on hw without
 		 * LLC and broken snooping.
 		 */
@@ -777,24 +478,11 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
 	}
 
 	if (args->flags & ~(I915_USERPTR_READ_ONLY |
-			    I915_USERPTR_UNSYNCHRONIZED))
+			    I915_USERPTR_UNSYNCHRONIZED |
+			    I915_USERPTR_PROBE))
 		return -EINVAL;
 
-	/*
-	 * XXX: There is a prevalence of the assumption that we fit the
-	 * object's page count inside a 32bit _signed_ variable. Let's document
-	 * this and catch if we ever need to fix it. In the meantime, if you do
-	 * spot such a local variable, please consider fixing!
-	 *
-	 * Aside from our own locals (for which we have no excuse!):
-	 * - sg_table embeds unsigned int for num_pages
-	 * - get_user_pages*() mixed ints with longs
-	 */
-
-	if (args->user_size >> PAGE_SHIFT > INT_MAX)
-		return -E2BIG;
-
-	if (overflows_type(args->user_size, obj->base.size))
+	if (i915_gem_object_size_2big(args->user_size))
 		return -E2BIG;
 
 	if (!args->user_size)
@@ -806,26 +494,43 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
 	if (!access_ok((char __user *)(unsigned long)args->user_ptr, args->user_size))
 		return -EFAULT;
 
+	if (args->flags & I915_USERPTR_UNSYNCHRONIZED)
+		return -ENODEV;
+
 	if (args->flags & I915_USERPTR_READ_ONLY) {
 		/*
 		 * On almost all of the older hw, we cannot tell the GPU that
 		 * a page is readonly.
 		 */
-		if (!dev_priv->gt.vm->has_read_only)
+		if (!to_gt(i915)->vm->has_read_only)
 			return -ENODEV;
 	}
 
+	if (args->flags & I915_USERPTR_PROBE) {
+		/*
+		 * Check that the range pointed to represents real struct
+		 * pages and not iomappings (at this moment in time!)
+		 */
+		ret = probe_range(current->mm, args->user_ptr, args->user_size);
+		if (ret)
+			return ret;
+	}
+
+#ifdef CONFIG_MMU_NOTIFIER
 	obj = i915_gem_object_alloc();
 	if (obj == NULL)
 		return -ENOMEM;
 
 	drm_gem_private_object_init(dev, &obj->base, args->user_size);
-	i915_gem_object_init(obj, &i915_gem_userptr_ops, &lock_class);
+	i915_gem_object_init(obj, &i915_gem_userptr_ops, &lock_class,
+			     I915_BO_ALLOC_USER);
+	obj->mem_flags = I915_BO_FLAG_STRUCT_PAGE;
 	obj->read_domains = I915_GEM_DOMAIN_CPU;
 	obj->write_domain = I915_GEM_DOMAIN_CPU;
 	i915_gem_object_set_cache_coherency(obj, I915_CACHE_LLC);
 
 	obj->userptr.ptr = args->user_ptr;
+	obj->userptr.notifier_seq = ULONG_MAX;
 	if (args->flags & I915_USERPTR_READ_ONLY)
 		i915_gem_object_set_readonly(obj);
 
@@ -833,9 +538,7 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
 	 * at binding. This means that we need to hook into the mmu_notifier
 	 * in order to detect if the mmu is destroyed.
 	 */
-	ret = i915_gem_userptr_init__mm_struct(obj);
-	if (ret == 0)
-		ret = i915_gem_userptr_init__mmu_notifier(obj, args->flags);
+	ret = i915_gem_userptr_init__mmu_notifier(obj);
 	if (ret == 0)
 		ret = drm_gem_handle_create(file, &obj->base, &handle);
 
@@ -846,24 +549,8 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
 
 	args->handle = handle;
 	return 0;
+#else
+	return -ENODEV;
+#endif
 }
 
-int i915_gem_init_userptr(struct drm_i915_private *dev_priv)
-{
-	mutex_init(&dev_priv->mm_lock);
-	hash_init(dev_priv->mm_structs);
-
-	dev_priv->mm.userptr_wq =
-		alloc_workqueue("i915-userptr-acquire",
-				WQ_HIGHPRI | WQ_UNBOUND,
-				0);
-	if (!dev_priv->mm.userptr_wq)
-		return -ENOMEM;
-
-	return 0;
-}
-
-void i915_gem_cleanup_userptr(struct drm_i915_private *dev_priv)
-{
-	destroy_workqueue(dev_priv->mm.userptr_wq);
-}