linux/drivers/gpu/drm/i915/i915_gem_userptr.c

848 lines
22 KiB
C

/*
* Copyright © 2012-2014 Intel Corporation
*
* 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, sublicense,
* 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 above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* 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 NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS 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.
*
*/
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_trace.h"
#include "intel_drv.h"
#include <linux/mmu_context.h>
#include <linux/mmu_notifier.h>
#include <linux/mempolicy.h>
#include <linux/swap.h>
#include <linux/sched/mm.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);
}
static void
__i915_gem_userptr_set_active(struct drm_i915_gem_object *obj, bool value)
{
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);
}
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;
struct mutex *unlock = NULL;
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);
if (!unlock) {
unlock = &mn->mm->i915->drm.struct_mutex;
switch (mutex_trylock_recursive(unlock)) {
default:
case MUTEX_TRYLOCK_FAILED:
if (mutex_lock_killable_nested(unlock, I915_MM_SHRINKER)) {
i915_gem_object_put(obj);
return -EINTR;
}
/* fall through */
case MUTEX_TRYLOCK_SUCCESS:
break;
case MUTEX_TRYLOCK_RECURSIVE:
unlock = ERR_PTR(-EEXIST);
break;
}
}
ret = i915_gem_object_unbind(obj);
if (ret == 0)
ret = __i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
i915_gem_object_put(obj);
if (ret)
goto unlock;
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);
unlock:
if (!IS_ERR_OR_NULL(unlock))
mutex_unlock(unlock);
return ret;
}
static const struct mmu_notifier_ops i915_gem_userptr_notifier = {
.invalidate_range_start = userptr_mn_invalidate_range_start,
};
static struct i915_mmu_notifier *
i915_mmu_notifier_create(struct i915_mm_struct *mm)
{
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;
}
static void
i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj)
{
struct i915_mmu_object *mo;
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);
}
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);
down_write(&mm->mm->mmap_sem);
mutex_lock(&mm->i915->mm_lock);
if (mm->mn == NULL && !err) {
/* Protected by mmap_sem (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;
}
mutex_unlock(&mm->i915->mm_lock);
up_write(&mm->mm->mmap_sem);
if (mn && !IS_ERR(mn))
kfree(mn);
return err ? ERR_PTR(err) : mm->mn;
}
static int
i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj,
unsigned flags)
{
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;
mn = i915_mmu_notifier_find(obj->userptr.mm);
if (IS_ERR(mn))
return PTR_ERR(mn);
mo = kzalloc(sizeof(*mo), GFP_KERNEL);
if (!mo)
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;
}
static void
i915_mmu_notifier_free(struct i915_mmu_notifier *mn,
struct mm_struct *mm)
{
if (mn == NULL)
return;
mmu_notifier_unregister(&mn->mn, mm);
kfree(mn);
}
#else
static void
__i915_gem_userptr_set_active(struct drm_i915_gem_object *obj, bool value)
{
}
static void
i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj)
{
}
static int
i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj,
unsigned flags)
{
if ((flags & I915_USERPTR_UNSYNCHRONIZED) == 0)
return -ENODEV;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return 0;
}
static void
i915_mmu_notifier_free(struct i915_mmu_notifier *mn,
struct mm_struct *mm)
{
}
#endif
static struct i915_mm_struct *
__i915_mm_struct_find(struct drm_i915_private *dev_priv, struct mm_struct *real)
{
struct i915_mm_struct *mm;
/* 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;
return NULL;
}
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.
*/
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);
mm->mm = current->mm;
mmgrab(current->mm);
mm->mn = NULL;
/* Protected by dev_priv->mm_lock */
hash_add(dev_priv->mm_structs,
&mm->node, (unsigned long)mm->mm);
} else
kref_get(&mm->kref);
obj->userptr.mm = mm;
out:
mutex_unlock(&dev_priv->mm_lock);
return ret;
}
static void
__i915_mm_struct_free__worker(struct work_struct *work)
{
struct i915_mm_struct *mm = container_of(work, typeof(*mm), work);
i915_mmu_notifier_free(mm->mn, mm->mm);
mmdrop(mm->mm);
kfree(mm);
}
static void
__i915_mm_struct_free(struct kref *kref)
{
struct i915_mm_struct *mm = container_of(kref, typeof(*mm), kref);
/* Protected by dev_priv->mm_lock */
hash_del(&mm->node);
mutex_unlock(&mm->i915->mm_lock);
INIT_WORK(&mm->work, __i915_mm_struct_free__worker);
queue_work(mm->i915->mm.userptr_wq, &mm->work);
}
static void
i915_gem_userptr_release__mm_struct(struct drm_i915_gem_object *obj)
{
if (obj->userptr.mm == NULL)
return;
kref_put_mutex(&obj->userptr.mm->kref,
__i915_mm_struct_free,
&to_i915(obj->base.dev)->mm_lock);
obj->userptr.mm = NULL;
}
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, int num_pages)
{
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);
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);
}
ret = i915_gem_gtt_prepare_pages(obj, st);
if (ret) {
sg_free_table(st);
if (max_segment > PAGE_SIZE) {
max_segment = PAGE_SIZE;
goto alloc_table;
}
kfree(st);
return ERR_PTR(ret);
}
sg_page_sizes = i915_sg_page_sizes(st->sgl);
__i915_gem_object_set_pages(obj, st, sg_page_sizes);
return st;
}
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 int npages = obj->base.size >> PAGE_SHIFT;
struct page **pvec;
int pinned, ret;
ret = -ENOMEM;
pinned = 0;
pvec = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
if (pvec != NULL) {
struct mm_struct *mm = obj->userptr.mm->mm;
unsigned int flags = 0;
if (!i915_gem_object_is_readonly(obj))
flags |= FOLL_WRITE;
ret = -EFAULT;
if (mmget_not_zero(mm)) {
down_read(&mm->mmap_sem);
while (pinned < npages) {
ret = get_user_pages_remote
(work->task, mm,
obj->userptr.ptr + pinned * PAGE_SIZE,
npages - pinned,
flags,
pvec + pinned, NULL, NULL);
if (ret < 0)
break;
pinned += ret;
}
up_read(&mm->mmap_sem);
mmput(mm);
}
}
mutex_lock(&obj->mm.lock);
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;
}
}
obj->userptr.work = ERR_CAST(pages);
if (IS_ERR(pages))
__i915_gem_userptr_set_active(obj, false);
}
mutex_unlock(&obj->mm.lock);
release_pages(pvec, pinned);
kvfree(pvec);
i915_gem_object_put(obj);
put_task_struct(work->task);
kfree(work);
}
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_sem, and we have
* a strict lock ordering of mmap_sem, 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);
obj->userptr.work = &work->work;
work->obj = i915_gem_object_get(obj);
work->task = current;
get_task_struct(work->task);
INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker);
queue_work(to_i915(obj->base.dev)->mm.userptr_wq, &work->work);
return ERR_PTR(-EAGAIN);
}
static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
{
const int 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;
/* 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;
}
pvec = NULL;
pinned = 0;
if (mm == current->mm) {
pvec = kvmalloc_array(num_pages, sizeof(struct page *),
GFP_KERNEL |
__GFP_NORETRY |
__GFP_NOWARN);
if (pvec) /* defer to worker if malloc fails */
pinned = __get_user_pages_fast(obj->userptr.ptr,
num_pages,
!i915_gem_object_is_readonly(obj),
pvec);
}
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);
}
if (active)
__i915_gem_userptr_set_active(obj, true);
if (IS_ERR(pages))
release_pages(pvec, pinned);
kvfree(pvec);
return PTR_ERR_OR_ZERO(pages);
}
static void
i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
struct sg_table *pages)
{
struct sgt_iter sgt_iter;
struct page *page;
/* Cancel any inflight work and force them to restart their gup */
obj->userptr.work = NULL;
__i915_gem_userptr_set_active(obj, false);
if (!pages)
return;
__i915_gem_object_release_shmem(obj, pages, true);
i915_gem_gtt_finish_pages(obj, pages);
for_each_sgt_page(page, sgt_iter, pages) {
if (obj->mm.dirty)
set_page_dirty(page);
mark_page_accessed(page);
put_page(page);
}
obj->mm.dirty = false;
sg_free_table(pages);
kfree(pages);
}
static void
i915_gem_userptr_release(struct drm_i915_gem_object *obj)
{
i915_gem_userptr_release__mmu_notifier(obj);
i915_gem_userptr_release__mm_struct(obj);
}
static int
i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj)
{
if (obj->userptr.mmu_object)
return 0;
return i915_gem_userptr_init__mmu_notifier(obj, 0);
}
static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
I915_GEM_OBJECT_IS_SHRINKABLE |
I915_GEM_OBJECT_ASYNC_CANCEL,
.get_pages = i915_gem_userptr_get_pages,
.put_pages = i915_gem_userptr_put_pages,
.dmabuf_export = i915_gem_userptr_dmabuf_export,
.release = i915_gem_userptr_release,
};
/*
* Creates a new mm object that wraps some normal memory from the process
* context - user memory.
*
* We impose several restrictions upon the memory being mapped
* into the GPU.
* 1. It must be page aligned (both start/end addresses, i.e ptr and size).
* 2. It must be normal system memory, not a pointer into another map of IO
* space (e.g. it must not be a GTT mmapping of another object).
* 3. We only allow a bo as large as we could in theory map into the GTT,
* that is we limit the size to the total size of the GTT.
* 4. The bo is marked as being snoopable. The backing pages are left
* accessible directly by the CPU, but reads and writes by the GPU may
* incur the cost of a snoop (unless you have an LLC architecture).
*
* Synchronisation between multiple users and the GPU is left to userspace
* through the normal set-domain-ioctl. The kernel will enforce that the
* GPU relinquishes the VMA before it is returned back to the system
* i.e. upon free(), munmap() or process termination. However, the userspace
* malloc() library may not immediately relinquish the VMA after free() and
* instead reuse it whilst the GPU is still reading and writing to the VMA.
* Caveat emptor.
*
* Also note, that the object created here is not currently a "first class"
* object, in that several ioctls are banned. These are the CPU access
* ioctls: mmap(), pwrite and pread. In practice, you are expected to use
* direct access via your pointer rather than use those ioctls. Another
* restriction is that we do not allow userptr surfaces to be pinned to the
* hardware and so we reject any attempt to create a framebuffer out of a
* userptr.
*
* If you think this is a good interface to use to pass GPU memory between
* drivers, please use dma-buf instead. In fact, wherever possible use
* dma-buf instead.
*/
int
i915_gem_userptr_ioctl(struct drm_device *dev,
void *data,
struct drm_file *file)
{
struct drm_i915_private *dev_priv = to_i915(dev);
struct drm_i915_gem_userptr *args = data;
struct drm_i915_gem_object *obj;
int ret;
u32 handle;
if (!HAS_LLC(dev_priv) && !HAS_SNOOP(dev_priv)) {
/* We cannot support coherent userptr objects on hw without
* LLC and broken snooping.
*/
return -ENODEV;
}
if (args->flags & ~(I915_USERPTR_READ_ONLY |
I915_USERPTR_UNSYNCHRONIZED))
return -EINVAL;
if (!args->user_size)
return -EINVAL;
if (offset_in_page(args->user_ptr | args->user_size))
return -EINVAL;
if (!access_ok((char __user *)(unsigned long)args->user_ptr, args->user_size))
return -EFAULT;
if (args->flags & I915_USERPTR_READ_ONLY) {
struct i915_hw_ppgtt *ppgtt;
/*
* On almost all of the older hw, we cannot tell the GPU that
* a page is readonly.
*/
ppgtt = dev_priv->kernel_context->ppgtt;
if (!ppgtt || !ppgtt->vm.has_read_only)
return -ENODEV;
}
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);
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;
if (args->flags & I915_USERPTR_READ_ONLY)
i915_gem_object_set_readonly(obj);
/* And keep a pointer to the current->mm for resolving the user pages
* 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);
if (ret == 0)
ret = drm_gem_handle_create(file, &obj->base, &handle);
/* drop reference from allocate - handle holds it now */
i915_gem_object_put(obj);
if (ret)
return ret;
args->handle = handle;
return 0;
}
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);
}