[Intel-gfx] [PATCH 3/3] drm/vgem: Attach sw fences to exported vGEM dma-buf (ioctl)

Zach Reizner zachr at google.com
Thu Jun 30 15:40:49 UTC 2016


On Thu, Jun 23, 2016 at 10:35 AM Chris Wilson <chris at chris-wilson.co.uk>
wrote:

> vGEM buffers are useful for passing data between software clients and
> hardware renders. By allowing the user to create and attach fences to
> the exported vGEM buffers (on the dma-buf), the user can implement a
> deferred renderer and queue hardware operations like flipping and then
> signal the buffer readiness (i.e. this allows the user to schedule
> operations out-of-order, but have them complete in-order).
>
> This also makes it much easier to write tightly controlled testcases for
> dma-buf fencing and signaling between hardware drivers.
>
> Testcase: igt/vgem_basic/dmabuf-fence
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Sean Paul <seanpaul at chromium.org>
> Cc: Zach Reizner <zachr at google.com>
> ---
>  drivers/gpu/drm/vgem/Makefile     |   2 +-
>  drivers/gpu/drm/vgem/vgem_drv.c   |  34 ++++++
>  drivers/gpu/drm/vgem/vgem_drv.h   |  18 ++++
>  drivers/gpu/drm/vgem/vgem_fence.c | 217
> ++++++++++++++++++++++++++++++++++++++
>  include/uapi/drm/vgem_drm.h       |  62 +++++++++++
>  5 files changed, 332 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/vgem/vgem_fence.c
>  create mode 100644 include/uapi/drm/vgem_drm.h
>
> diff --git a/drivers/gpu/drm/vgem/Makefile b/drivers/gpu/drm/vgem/Makefile
> index 3f4c7b842028..bfcdea1330e6 100644
> --- a/drivers/gpu/drm/vgem/Makefile
> +++ b/drivers/gpu/drm/vgem/Makefile
> @@ -1,4 +1,4 @@
>  ccflags-y := -Iinclude/drm
> -vgem-y := vgem_drv.o
> +vgem-y := vgem_drv.o vgem_fence.o
>
>  obj-$(CONFIG_DRM_VGEM) += vgem.o
> diff --git a/drivers/gpu/drm/vgem/vgem_drv.c
> b/drivers/gpu/drm/vgem/vgem_drv.c
> index 69468b5f3d82..56e348701382 100644
> --- a/drivers/gpu/drm/vgem/vgem_drv.c
> +++ b/drivers/gpu/drm/vgem/vgem_drv.c
> @@ -83,6 +83,34 @@ static const struct vm_operations_struct
> vgem_gem_vm_ops = {
>         .close = drm_gem_vm_close,
>  };
>
> +static int vgem_open(struct drm_device *dev, struct drm_file *file)
> +{
> +       struct vgem_file *vfile;
> +       int ret;
> +
> +       vfile = kzalloc(sizeof(*vfile), GFP_KERNEL);
> +       if (!vfile)
> +               return -ENOMEM;
> +
> +       file->driver_priv = vfile;
> +
> +       ret = vgem_fence_open(vfile);
> +       if (ret) {
> +               kfree(vfile);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static void vgem_preclose(struct drm_device *dev, struct drm_file *file)
> +{
> +       struct vgem_file *vfile = file->driver_priv;
> +
> +       vgem_fence_close(vfile);
> +       kfree(vfile);
> +}
> +
>  /* ioctls */
>
>  static struct drm_gem_object *vgem_gem_create(struct drm_device *dev,
> @@ -164,6 +192,8 @@ unref:
>  }
>
>  static struct drm_ioctl_desc vgem_ioctls[] = {
> +       DRM_IOCTL_DEF_DRV(VGEM_FENCE_ATTACH, vgem_fence_attach_ioctl,
> DRM_AUTH|DRM_RENDER_ALLOW),
> +       DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl,
> DRM_AUTH|DRM_RENDER_ALLOW),
>  };
>
>  static int vgem_mmap(struct file *filp, struct vm_area_struct *vma)
> @@ -286,9 +316,12 @@ static int vgem_prime_mmap(struct drm_gem_object *obj,
>
>  static struct drm_driver vgem_driver = {
>         .driver_features                = DRIVER_GEM | DRIVER_PRIME,
> +       .open                           = vgem_open,
> +       .preclose                       = vgem_preclose,
>         .gem_free_object_unlocked       = vgem_gem_free_object,
>         .gem_vm_ops                     = &vgem_gem_vm_ops,
>         .ioctls                         = vgem_ioctls,
> +       .num_ioctls                     = ARRAY_SIZE(vgem_ioctls),
>         .fops                           = &vgem_driver_fops,
>
>         .dumb_create                    = vgem_gem_dumb_create,
> @@ -343,5 +376,6 @@ module_init(vgem_init);
>  module_exit(vgem_exit);
>
>  MODULE_AUTHOR("Red Hat, Inc.");
> +MODULE_AUTHOR("Intel Corporation");
>  MODULE_DESCRIPTION(DRIVER_DESC);
>  MODULE_LICENSE("GPL and additional rights");
> diff --git a/drivers/gpu/drm/vgem/vgem_drv.h
> b/drivers/gpu/drm/vgem/vgem_drv.h
> index 988cbaae7588..88ce21010e28 100644
> --- a/drivers/gpu/drm/vgem/vgem_drv.h
> +++ b/drivers/gpu/drm/vgem/vgem_drv.h
> @@ -32,9 +32,27 @@
>  #include <drm/drmP.h>
>  #include <drm/drm_gem.h>
>
> +#include <uapi/drm/vgem_drm.h>
> +
> +struct vgem_file {
> +       struct idr fence_idr;
> +       struct mutex fence_mutex;
> +       u64 fence_context;
> +       atomic_t fence_seqno;
> +};
> +
>  #define to_vgem_bo(x) container_of(x, struct drm_vgem_gem_object, base)
>  struct drm_vgem_gem_object {
>         struct drm_gem_object base;
>  };
>
> +int vgem_fence_open(struct vgem_file *file);
> +int vgem_fence_attach_ioctl(struct drm_device *dev,
> +                           void *data,
> +                           struct drm_file *file);
> +int vgem_fence_signal_ioctl(struct drm_device *dev,
> +                           void *data,
> +                           struct drm_file *file);
> +void vgem_fence_close(struct vgem_file *file);
> +
>  #endif
> diff --git a/drivers/gpu/drm/vgem/vgem_fence.c
> b/drivers/gpu/drm/vgem/vgem_fence.c
> new file mode 100644
> index 000000000000..46130e4a3506
> --- /dev/null
> +++ b/drivers/gpu/drm/vgem/vgem_fence.c
> @@ -0,0 +1,217 @@
> +/*
> + * Copyright 2016 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
> + * on the rights to use, copy, modify, merge, publish, distribute, sub
> + * license, and/or sell copies of the Software, and to permit persons to
> whom
> + * them 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
> MERCHANTIBILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT
> SHALL
> + * THE AUTHORS 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 <linux/dma-buf.h>
> +#include <linux/reservation.h>
> +
> +#include "vgem_drv.h"
> +
> +struct vgem_fence {
> +       struct fence base;
> +       struct spinlock lock;
> +};
> +
> +static const char *vgem_fence_get_driver_name(struct fence *fence)
> +{
> +       return "vgem";
> +}
> +
> +static const char *vgem_fence_get_timeline_name(struct fence *fence)
> +{
> +       return "file";
> +}
> +
> +static bool vgem_fence_signaled(struct fence *fence)
> +{
> +       return false;
> +}
> +
> +static bool vgem_fence_enable_signaling(struct fence *fence)
> +{
> +       return true;
> +}
> +
> +static void vgem_fence_value_str(struct fence *fence, char *str, int size)
> +{
> +       snprintf(str, size, "%u", fence->seqno);
> +}
> +
> +static void vgem_fence_timeline_value_str(struct fence *fence, char *str,
> +                                         int size)
> +{
> +       snprintf(str, size, "%u", 0);
> +}
> +
> +const struct fence_ops vgem_fence_ops = {
> +       .get_driver_name = vgem_fence_get_driver_name,
> +       .get_timeline_name = vgem_fence_get_timeline_name,
> +       .enable_signaling = vgem_fence_enable_signaling,
> +       .signaled = vgem_fence_signaled,
> +       .wait = fence_default_wait,
> +       .fence_value_str = vgem_fence_value_str,
> +       .timeline_value_str = vgem_fence_timeline_value_str,
> +};
> +
> +static u32 vgem_fence_next_seqno(struct vgem_file *vfile)
> +{
> +       u32 seqno;
> +
> +       seqno = atomic_inc_return(&vfile->fence_seqno);
> +       if (seqno == 0)
> +               seqno = atomic_inc_return(&vfile->fence_seqno);
> +
> +       return seqno;
> +}
> +
> +static struct fence *vgem_fence_create(struct vgem_file *vfile)
> +{
> +       struct vgem_fence *fence;
> +
> +       fence = kzalloc(sizeof(*fence), GFP_KERNEL);
> +       if (!fence)
> +               return NULL;
> +
> +       spin_lock_init(&fence->lock);
> +       fence_init(&fence->base,
> +                  &vgem_fence_ops,
> +                  &fence->lock,
> +                  vfile->fence_context,
> +                  vgem_fence_next_seqno(vfile));
> +
> +       return &fence->base;
> +}
> +
> +static int attach_dmabuf(struct drm_device *dev,
> +                        struct drm_gem_object *obj)
> +{
> +       struct dma_buf *dmabuf;
> +
> +       if (obj->dma_buf)
> +               return 0;
> +
> +       dmabuf = dev->driver->gem_prime_export(dev, obj, 0);
> +       if (IS_ERR(dmabuf))
> +               return PTR_ERR(dmabuf);
> +
> +       obj->dma_buf = dmabuf;
> +       drm_gem_object_reference(obj);
> +       return 0;
> +}
> +
> +int vgem_fence_attach_ioctl(struct drm_device *dev,
> +                           void *data,
> +                           struct drm_file *file)
> +{
> +       struct drm_vgem_fence_attach *arg = data;
> +       struct vgem_file *vfile = file->driver_priv;
> +       struct reservation_object *resv;
> +       struct drm_gem_object *obj;
> +       struct fence *fence;
> +       int ret;
> +
> +       if (arg->flags & ~VGEM_FENCE_WRITE)
> +               return -EINVAL;
> +
> +       obj = drm_gem_object_lookup(file, arg->handle);
> +       if (!obj)
> +               return -ENOENT;
> +
> +       ret = attach_dmabuf(dev, obj);
> +       if (ret)
> +               goto out;
> +
> +       fence = vgem_fence_create(vfile);
> +       if (!fence) {
> +               ret = -ENOMEM;
> +               goto out;
> +       }
> +
> +       ret = 0;
> +       resv = obj->dma_buf->resv;
> +       mutex_lock(&resv->lock.base);
> +       if (arg->flags & VGEM_FENCE_WRITE)
> +               reservation_object_add_excl_fence(resv, fence);
> +       else if ((ret = reservation_object_reserve_shared(resv)) == 0)
> +               reservation_object_add_shared_fence(resv, fence);
> +       mutex_unlock(&resv->lock.base);
> +
> +       if (ret == 0) {
> +               mutex_lock(&vfile->fence_mutex);
> +               ret = idr_alloc(&vfile->fence_idr, fence, 1, 0,
> GFP_KERNEL);
> +               mutex_unlock(&vfile->fence_mutex);
> +               if (ret > 0) {
> +                       arg->out_fence = ret;
> +                       ret = 0;
> +               }
> +       }
> +       if (ret)
> +               fence_put(fence);
> +out:
> +       drm_gem_object_unreference_unlocked(obj);
> +       return ret;
> +}
> +
> +int vgem_fence_signal_ioctl(struct drm_device *dev,
> +                           void *data,
> +                           struct drm_file *file)
> +{
> +       struct vgem_file *vfile = file->driver_priv;
> +       struct drm_vgem_fence_signal *arg = data;
> +       struct fence *fence;
> +
> +       if (arg->flags)
> +               return -EINVAL;
> +
> +       mutex_lock(&vfile->fence_mutex);
> +       fence = idr_replace(&vfile->fence_idr, NULL, arg->fence);
> +       mutex_unlock(&vfile->fence_mutex);
> +       if (!fence)
> +               return -ENOENT;
> +       if (IS_ERR(fence))
> +               return PTR_ERR(fence);
> +
> +       fence_signal(fence);
> +       fence_put(fence);
> +       return 0;
> +}
> +
> +int vgem_fence_open(struct vgem_file *vfile)
> +{
> +       mutex_init(&vfile->fence_mutex);
> +       idr_init(&vfile->fence_idr);
> +       vfile->fence_context = fence_context_alloc(1);
> +
> +       return 0;
> +}
> +
> +static int __vgem_fence_idr_fini(int id, void *p, void *data)
> +{
> +       fence_signal(p);
> +       fence_put(p);
> +       return 0;
> +}
> +
> +void vgem_fence_close(struct vgem_file *vfile)
> +{
> +       idr_for_each(&vfile->fence_idr, __vgem_fence_idr_fini, vfile);
> +       idr_destroy(&vfile->fence_idr);
> +}
> diff --git a/include/uapi/drm/vgem_drm.h b/include/uapi/drm/vgem_drm.h
> new file mode 100644
> index 000000000000..352d2fae8de9
> --- /dev/null
> +++ b/include/uapi/drm/vgem_drm.h
> @@ -0,0 +1,62 @@
> +/*
> + * Copyright 2016 Intel Corporation
> + * 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 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 NON-INFRINGEMENT.
> + * IN NO EVENT SHALL TUNGSTEN GRAPHICS 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.
> + *
> + */
> +
> +#ifndef _UAPI_VGEM_DRM_H_
> +#define _UAPI_VGEM_DRM_H_
> +
> +#include "drm.h"
> +
> +#if defined(__cplusplus)
> +extern "C" {
> +#endif
> +
> +/* Please note that modifications to all structs defined here are
> + * subject to backwards-compatibility constraints.
> + */
> +#define DRM_VGEM_FENCE_ATTACH  0x1
> +#define DRM_VGEM_FENCE_SIGNAL  0x2
> +
> +#define DRM_IOCTL_VGEM_FENCE_ATTACH    DRM_IOWR( DRM_COMMAND_BASE +
> DRM_VGEM_FENCE_ATTACH, struct drm_vgem_fence_attach)
> +#define DRM_IOCTL_VGEM_FENCE_SIGNAL    DRM_IOW( DRM_COMMAND_BASE +
> DRM_VGEM_FENCE_SIGNAL, struct drm_vgem_fence_signal)
> +
> +struct drm_vgem_fence_attach {
> +       __u32 handle;
> +       __u32 flags;
> +#define VGEM_FENCE_WRITE 0x1
> +       __u32 out_fence;
> +       __u32 pad;
> +};
> +
> +struct drm_vgem_fence_signal {
> +       __u32 fence;
> +       __u32 flags;
> +};
> +
> +#if defined(__cplusplus)
> +}
> +#endif
> +
> +#endif /* _UAPI_VGEM_DRM_H_ */
> --
> 2.8.1
>
Acked-by: Zach Reizner <zachr at google.com>
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