| Message ID | 20210408093448.3897988-1-stevensd@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/syncobj: use newly allocated stub fences | expand |
Sorry, I forgot to checkpatch this, I'll resend it momentarily. -David On Thu, Apr 8, 2021 at 6:34 PM David Stevens <stevensd@chromium.org> wrote: > > From: David Stevens <stevensd@chromium.org> > > Allocate a new private stub fence in drm_syncobj_assign_null_handle, > instead of using a static stub fence. > > When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when > userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp > obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO > should match when the fence's status was changed from the perspective of > userspace, which is during the respective ioctl. > > When a static stub fence started being used in by these ioctls, this > behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO > became the first time anything used the static stub fence, which has no > meaning to userspace. > > Signed-off-by: David Stevens <stevensd@chromium.org> > --- > drivers/dma-buf/dma-fence.c | 33 ++++++++++++++++++++++++++++++++- > drivers/gpu/drm/drm_syncobj.c | 28 ++++++++++++++++++++-------- > include/linux/dma-fence.h | 1 + > 3 files changed, 53 insertions(+), 9 deletions(-) > > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c > index d64fc03929be..6081eb962490 100644 > --- a/drivers/dma-buf/dma-fence.c > +++ b/drivers/dma-buf/dma-fence.c > @@ -26,6 +26,11 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled); > static DEFINE_SPINLOCK(dma_fence_stub_lock); > static struct dma_fence dma_fence_stub; > > +struct drm_fence_private_stub { > + struct dma_fence base; > + spinlock_t lock; > +}; > + > /* > * fence context counter: each execution context should have its own > * fence context, this allows checking if fences belong to the same > @@ -123,7 +128,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { > /** > * dma_fence_get_stub - return a signaled fence > * > - * Return a stub fence which is already signaled. > + * Return a stub fence which is already signaled. The fence's > + * timestamp corresponds to the first time after boot this > + * function is called. > */ > struct dma_fence *dma_fence_get_stub(void) > { > @@ -141,6 +148,30 @@ struct dma_fence *dma_fence_get_stub(void) > } > EXPORT_SYMBOL(dma_fence_get_stub); > > +/** > + * dma_fence_allocate_private_stub - return a private, signaled fence > + * > + * Return a newly allocated and signaled stub fence. > + */ > +struct dma_fence *dma_fence_allocate_private_stub(void) > +{ > + struct drm_fence_private_stub *fence; > + > + fence = kzalloc(sizeof(*fence), GFP_KERNEL); > + if (fence == NULL) > + return ERR_PTR(-ENOMEM); > + > + spin_lock_init(&fence->lock); > + dma_fence_init(&fence->base, > + &dma_fence_stub_ops, > + &fence->lock, > + 0, 0); > + dma_fence_signal(&fence->base); > + > + return &fence->base; > +} > +EXPORT_SYMBOL(dma_fence_allocate_private_stub); > + > /** > * dma_fence_context_alloc - allocate an array of fence contexts > * @num: amount of contexts to allocate > diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c > index 349146049849..c6125e57ae37 100644 > --- a/drivers/gpu/drm/drm_syncobj.c > +++ b/drivers/gpu/drm/drm_syncobj.c > @@ -350,12 +350,15 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); > * > * Assign a already signaled stub fence to the sync object. > */ > -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) > +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) > { > - struct dma_fence *fence = dma_fence_get_stub(); > + struct dma_fence *fence = dma_fence_allocate_private_stub(); > + if (IS_ERR(fence)) > + return PTR_ERR(fence); > > - drm_syncobj_replace_fence(syncobj, fence); > - dma_fence_put(fence); > + drm_syncobj_replace_fence(syncobj, fence); > + dma_fence_put(fence); > + return 0; > } > > /* 5s default for wait submission */ > @@ -469,6 +472,7 @@ EXPORT_SYMBOL(drm_syncobj_free); > int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, > struct dma_fence *fence) > { > + int ret; > struct drm_syncobj *syncobj; > > syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); > @@ -479,8 +483,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, > INIT_LIST_HEAD(&syncobj->cb_list); > spin_lock_init(&syncobj->lock); > > - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) > - drm_syncobj_assign_null_handle(syncobj); > + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { > + ret = drm_syncobj_assign_null_handle(syncobj); > + if (ret < 0) { > + drm_syncobj_put(syncobj); > + return ret; > + } > + } > > if (fence) > drm_syncobj_replace_fence(syncobj, fence); > @@ -1322,8 +1331,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, > if (ret < 0) > return ret; > > - for (i = 0; i < args->count_handles; i++) > - drm_syncobj_assign_null_handle(syncobjs[i]); > + for (i = 0; i < args->count_handles; i++) { > + ret = drm_syncobj_assign_null_handle(syncobjs[i]); > + if (ret < 0) > + break; > + } > > drm_syncobj_array_free(syncobjs, args->count_handles); > > diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h > index 9f12efaaa93a..6ffb4b2c6371 100644 > --- a/include/linux/dma-fence.h > +++ b/include/linux/dma-fence.h > @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) > } > > struct dma_fence *dma_fence_get_stub(void); > +struct dma_fence *dma_fence_allocate_private_stub(void); > u64 dma_fence_context_alloc(unsigned num); > > #define DMA_FENCE_TRACE(f, fmt, args...) \ > -- > 2.31.0.208.g409f899ff0-goog >
Am 08.04.21 um 11:34 schrieb David Stevens: > From: David Stevens <stevensd@chromium.org> > > Allocate a new private stub fence in drm_syncobj_assign_null_handle, > instead of using a static stub fence. > > When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when > userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp > obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO > should match when the fence's status was changed from the perspective of > userspace, which is during the respective ioctl. > > When a static stub fence started being used in by these ioctls, this > behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO > became the first time anything used the static stub fence, which has no > meaning to userspace. > > Signed-off-by: David Stevens <stevensd@chromium.org> > --- > drivers/dma-buf/dma-fence.c | 33 ++++++++++++++++++++++++++++++++- > drivers/gpu/drm/drm_syncobj.c | 28 ++++++++++++++++++++-------- > include/linux/dma-fence.h | 1 + > 3 files changed, 53 insertions(+), 9 deletions(-) > > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c > index d64fc03929be..6081eb962490 100644 > --- a/drivers/dma-buf/dma-fence.c > +++ b/drivers/dma-buf/dma-fence.c > @@ -26,6 +26,11 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled); > static DEFINE_SPINLOCK(dma_fence_stub_lock); > static struct dma_fence dma_fence_stub; > > +struct drm_fence_private_stub { > + struct dma_fence base; > + spinlock_t lock; > +}; > + You can drop this. The spinlock is only used when the fence is signaled to avoid races between signaling and adding a callback. And for this the global spinlock should be perfectly sufficient. Apart from that looks good to me. Regards, Christian. > /* > * fence context counter: each execution context should have its own > * fence context, this allows checking if fences belong to the same > @@ -123,7 +128,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { > /** > * dma_fence_get_stub - return a signaled fence > * > - * Return a stub fence which is already signaled. > + * Return a stub fence which is already signaled. The fence's > + * timestamp corresponds to the first time after boot this > + * function is called. > */ > struct dma_fence *dma_fence_get_stub(void) > { > @@ -141,6 +148,30 @@ struct dma_fence *dma_fence_get_stub(void) > } > EXPORT_SYMBOL(dma_fence_get_stub); > > +/** > + * dma_fence_allocate_private_stub - return a private, signaled fence > + * > + * Return a newly allocated and signaled stub fence. > + */ > +struct dma_fence *dma_fence_allocate_private_stub(void) > +{ > + struct drm_fence_private_stub *fence; > + > + fence = kzalloc(sizeof(*fence), GFP_KERNEL); > + if (fence == NULL) > + return ERR_PTR(-ENOMEM); > + > + spin_lock_init(&fence->lock); > + dma_fence_init(&fence->base, > + &dma_fence_stub_ops, > + &fence->lock, > + 0, 0); > + dma_fence_signal(&fence->base); > + > + return &fence->base; > +} > +EXPORT_SYMBOL(dma_fence_allocate_private_stub); > + > /** > * dma_fence_context_alloc - allocate an array of fence contexts > * @num: amount of contexts to allocate > diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c > index 349146049849..c6125e57ae37 100644 > --- a/drivers/gpu/drm/drm_syncobj.c > +++ b/drivers/gpu/drm/drm_syncobj.c > @@ -350,12 +350,15 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); > * > * Assign a already signaled stub fence to the sync object. > */ > -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) > +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) > { > - struct dma_fence *fence = dma_fence_get_stub(); > + struct dma_fence *fence = dma_fence_allocate_private_stub(); > + if (IS_ERR(fence)) > + return PTR_ERR(fence); > > - drm_syncobj_replace_fence(syncobj, fence); > - dma_fence_put(fence); > + drm_syncobj_replace_fence(syncobj, fence); > + dma_fence_put(fence); > + return 0; > } > > /* 5s default for wait submission */ > @@ -469,6 +472,7 @@ EXPORT_SYMBOL(drm_syncobj_free); > int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, > struct dma_fence *fence) > { > + int ret; > struct drm_syncobj *syncobj; > > syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); > @@ -479,8 +483,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, > INIT_LIST_HEAD(&syncobj->cb_list); > spin_lock_init(&syncobj->lock); > > - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) > - drm_syncobj_assign_null_handle(syncobj); > + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { > + ret = drm_syncobj_assign_null_handle(syncobj); > + if (ret < 0) { > + drm_syncobj_put(syncobj); > + return ret; > + } > + } > > if (fence) > drm_syncobj_replace_fence(syncobj, fence); > @@ -1322,8 +1331,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, > if (ret < 0) > return ret; > > - for (i = 0; i < args->count_handles; i++) > - drm_syncobj_assign_null_handle(syncobjs[i]); > + for (i = 0; i < args->count_handles; i++) { > + ret = drm_syncobj_assign_null_handle(syncobjs[i]); > + if (ret < 0) > + break; > + } > > drm_syncobj_array_free(syncobjs, args->count_handles); > > diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h > index 9f12efaaa93a..6ffb4b2c6371 100644 > --- a/include/linux/dma-fence.h > +++ b/include/linux/dma-fence.h > @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) > } > > struct dma_fence *dma_fence_get_stub(void); > +struct dma_fence *dma_fence_allocate_private_stub(void); > u64 dma_fence_context_alloc(unsigned num); > > #define DMA_FENCE_TRACE(f, fmt, args...) \
On Thu, Apr 08, 2021 at 06:34:48PM +0900, David Stevens wrote: > From: David Stevens <stevensd@chromium.org> > > Allocate a new private stub fence in drm_syncobj_assign_null_handle, > instead of using a static stub fence. > > When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when > userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp > obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO > should match when the fence's status was changed from the perspective of > userspace, which is during the respective ioctl. > > When a static stub fence started being used in by these ioctls, this > behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO > became the first time anything used the static stub fence, which has no > meaning to userspace. > > Signed-off-by: David Stevens <stevensd@chromium.org> Is there also an igt patch to enforce this in the drm_syncobj testcases? Would be really good to have that too. -Daniel > --- > drivers/dma-buf/dma-fence.c | 33 ++++++++++++++++++++++++++++++++- > drivers/gpu/drm/drm_syncobj.c | 28 ++++++++++++++++++++-------- > include/linux/dma-fence.h | 1 + > 3 files changed, 53 insertions(+), 9 deletions(-) > > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c > index d64fc03929be..6081eb962490 100644 > --- a/drivers/dma-buf/dma-fence.c > +++ b/drivers/dma-buf/dma-fence.c > @@ -26,6 +26,11 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled); > static DEFINE_SPINLOCK(dma_fence_stub_lock); > static struct dma_fence dma_fence_stub; > > +struct drm_fence_private_stub { > + struct dma_fence base; > + spinlock_t lock; > +}; > + > /* > * fence context counter: each execution context should have its own > * fence context, this allows checking if fences belong to the same > @@ -123,7 +128,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { > /** > * dma_fence_get_stub - return a signaled fence > * > - * Return a stub fence which is already signaled. > + * Return a stub fence which is already signaled. The fence's > + * timestamp corresponds to the first time after boot this > + * function is called. > */ > struct dma_fence *dma_fence_get_stub(void) > { > @@ -141,6 +148,30 @@ struct dma_fence *dma_fence_get_stub(void) > } > EXPORT_SYMBOL(dma_fence_get_stub); > > +/** > + * dma_fence_allocate_private_stub - return a private, signaled fence > + * > + * Return a newly allocated and signaled stub fence. > + */ > +struct dma_fence *dma_fence_allocate_private_stub(void) > +{ > + struct drm_fence_private_stub *fence; > + > + fence = kzalloc(sizeof(*fence), GFP_KERNEL); > + if (fence == NULL) > + return ERR_PTR(-ENOMEM); > + > + spin_lock_init(&fence->lock); > + dma_fence_init(&fence->base, > + &dma_fence_stub_ops, > + &fence->lock, > + 0, 0); > + dma_fence_signal(&fence->base); > + > + return &fence->base; > +} > +EXPORT_SYMBOL(dma_fence_allocate_private_stub); > + > /** > * dma_fence_context_alloc - allocate an array of fence contexts > * @num: amount of contexts to allocate > diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c > index 349146049849..c6125e57ae37 100644 > --- a/drivers/gpu/drm/drm_syncobj.c > +++ b/drivers/gpu/drm/drm_syncobj.c > @@ -350,12 +350,15 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); > * > * Assign a already signaled stub fence to the sync object. > */ > -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) > +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) > { > - struct dma_fence *fence = dma_fence_get_stub(); > + struct dma_fence *fence = dma_fence_allocate_private_stub(); > + if (IS_ERR(fence)) > + return PTR_ERR(fence); > > - drm_syncobj_replace_fence(syncobj, fence); > - dma_fence_put(fence); > + drm_syncobj_replace_fence(syncobj, fence); > + dma_fence_put(fence); > + return 0; > } > > /* 5s default for wait submission */ > @@ -469,6 +472,7 @@ EXPORT_SYMBOL(drm_syncobj_free); > int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, > struct dma_fence *fence) > { > + int ret; > struct drm_syncobj *syncobj; > > syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); > @@ -479,8 +483,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, > INIT_LIST_HEAD(&syncobj->cb_list); > spin_lock_init(&syncobj->lock); > > - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) > - drm_syncobj_assign_null_handle(syncobj); > + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { > + ret = drm_syncobj_assign_null_handle(syncobj); > + if (ret < 0) { > + drm_syncobj_put(syncobj); > + return ret; > + } > + } > > if (fence) > drm_syncobj_replace_fence(syncobj, fence); > @@ -1322,8 +1331,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, > if (ret < 0) > return ret; > > - for (i = 0; i < args->count_handles; i++) > - drm_syncobj_assign_null_handle(syncobjs[i]); > + for (i = 0; i < args->count_handles; i++) { > + ret = drm_syncobj_assign_null_handle(syncobjs[i]); > + if (ret < 0) > + break; > + } > > drm_syncobj_array_free(syncobjs, args->count_handles); > > diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h > index 9f12efaaa93a..6ffb4b2c6371 100644 > --- a/include/linux/dma-fence.h > +++ b/include/linux/dma-fence.h > @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) > } > > struct dma_fence *dma_fence_get_stub(void); > +struct dma_fence *dma_fence_allocate_private_stub(void); > u64 dma_fence_context_alloc(unsigned num); > > #define DMA_FENCE_TRACE(f, fmt, args...) \ > -- > 2.31.0.208.g409f899ff0-goog >
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index d64fc03929be..6081eb962490 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -26,6 +26,11 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled); static DEFINE_SPINLOCK(dma_fence_stub_lock); static struct dma_fence dma_fence_stub; +struct drm_fence_private_stub { + struct dma_fence base; + spinlock_t lock; +}; + /* * fence context counter: each execution context should have its own * fence context, this allows checking if fences belong to the same @@ -123,7 +128,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { /** * dma_fence_get_stub - return a signaled fence * - * Return a stub fence which is already signaled. + * Return a stub fence which is already signaled. The fence's + * timestamp corresponds to the first time after boot this + * function is called. */ struct dma_fence *dma_fence_get_stub(void) { @@ -141,6 +148,30 @@ struct dma_fence *dma_fence_get_stub(void) } EXPORT_SYMBOL(dma_fence_get_stub); +/** + * dma_fence_allocate_private_stub - return a private, signaled fence + * + * Return a newly allocated and signaled stub fence. + */ +struct dma_fence *dma_fence_allocate_private_stub(void) +{ + struct drm_fence_private_stub *fence; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&fence->lock); + dma_fence_init(&fence->base, + &dma_fence_stub_ops, + &fence->lock, + 0, 0); + dma_fence_signal(&fence->base); + + return &fence->base; +} +EXPORT_SYMBOL(dma_fence_allocate_private_stub); + /** * dma_fence_context_alloc - allocate an array of fence contexts * @num: amount of contexts to allocate diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..c6125e57ae37 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -350,12 +350,15 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); * * Assign a already signaled stub fence to the sync object. */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct dma_fence *fence = dma_fence_allocate_private_stub(); + if (IS_ERR(fence)) + return PTR_ERR(fence); - drm_syncobj_replace_fence(syncobj, fence); - dma_fence_put(fence); + drm_syncobj_replace_fence(syncobj, fence); + dma_fence_put(fence); + return 0; } /* 5s default for wait submission */ @@ -469,6 +472,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +483,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1331,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 9f12efaaa93a..6ffb4b2c6371 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) } struct dma_fence *dma_fence_get_stub(void); +struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); #define DMA_FENCE_TRACE(f, fmt, args...) \