[PATCH 2/5] drm/syncobj: add sync obj wait interface. (v3)

Jason Ekstrand jason at jlekstrand.net
Wed May 24 17:25:03 UTC 2017


On Wed, May 24, 2017 at 12:06 AM, Dave Airlie <airlied at gmail.com> wrote:

> From: Dave Airlie <airlied at redhat.com>
>
> This interface will allow sync object to be used to back
> Vulkan fences. This API is pretty much the vulkan fence waiting
> API, and I've ported the code from amdgpu.
>
> v2: accept relative timeout, pass remaining time back
> to userspace.
> v3: return to absolute timeouts.
>
> Signed-off-by: Dave Airlie <airlied at redhat.com>
> ---
>  drivers/gpu/drm/drm_internal.h |   2 +
>  drivers/gpu/drm/drm_ioctl.c    |   2 +
>  drivers/gpu/drm/drm_syncobj.c  | 164 ++++++++++++++++++++++++++++++
> +++++++++++
>  include/uapi/drm/drm.h         |  14 ++++
>  4 files changed, 182 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_
> internal.h
> index 3fdef2c..53e3f6b 100644
> --- a/drivers/gpu/drm/drm_internal.h
> +++ b/drivers/gpu/drm/drm_internal.h
> @@ -156,3 +156,5 @@ int drm_syncobj_handle_to_fd_ioctl(struct drm_device
> *dev, void *data,
>                                    struct drm_file *file_private);
>  int drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data,
>                                    struct drm_file *file_private);
> +int drm_syncobj_wait_ioctl(struct drm_device *dev, void *data,
> +                          struct drm_file *file_private);
> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> index f1e5681..385ce74 100644
> --- a/drivers/gpu/drm/drm_ioctl.c
> +++ b/drivers/gpu/drm/drm_ioctl.c
> @@ -657,6 +657,8 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
>                       DRM_UNLOCKED|DRM_RENDER_ALLOW),
>         DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_FD_TO_HANDLE,
> drm_syncobj_fd_to_handle_ioctl,
>                       DRM_UNLOCKED|DRM_RENDER_ALLOW),
> +       DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_WAIT, drm_syncobj_wait_ioctl,
> +                     DRM_UNLOCKED|DRM_RENDER_ALLOW),
>  };
>
>  #define DRM_CORE_IOCTL_COUNT   ARRAY_SIZE( drm_ioctls )
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index b611480..8b87594 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -1,5 +1,7 @@
>  /*
>   * Copyright 2017 Red Hat
> + * Parts ported from amdgpu (fence wait code).
> + * Copyright 2016 Advanced Micro Devices, Inc.
>   *
>   * Permission is hereby granted, free of charge, to any person obtaining a
>   * copy of this software and associated documentation files (the
> "Software"),
> @@ -31,6 +33,9 @@
>   * that contain an optional fence. The fence can be updated with a new
>   * fence, or be NULL.
>   *
> + * syncobj's can be waited upon, where it will wait for the underlying
> + * fence.
> + *
>   * syncobj's can be export to fd's and back, these fd's are opaque and
>   * have no other use case, except passing the syncobj between processes.
>   *
> @@ -375,3 +380,162 @@ drm_syncobj_fd_to_handle_ioctl(struct drm_device
> *dev, void *data,
>         return drm_syncobj_fd_to_handle(file_private, args->fd,
>                                         &args->handle);
>  }
> +
> +
> +/**
> + * drm_timeout_abs_to_jiffies - calculate jiffies timeout from absolute
> value
> + *
> + * @timeout_ns: timeout in ns
> + *
> + * Calculate the timeout in jiffies from an absolute timeout in ns.
> + */
> +unsigned long drm_timeout_abs_to_jiffies(uint64_t timeout_ns)
> +{
> +       unsigned long timeout_jiffies;
> +       ktime_t timeout;
> +
> +       /* clamp timeout if it's to large */
> +       if (((int64_t)timeout_ns) < 0)
> +               return MAX_SCHEDULE_TIMEOUT;
> +
> +       timeout = ktime_sub(ns_to_ktime(timeout_ns), ktime_get());
> +       if (ktime_to_ns(timeout) < 0)
> +               return 0;
> +
> +       timeout_jiffies = nsecs_to_jiffies(ktime_to_ns(timeout));
> +       /*  clamp timeout to avoid unsigned-> signed overflow */
> +       if (timeout_jiffies > MAX_SCHEDULE_TIMEOUT )
> +               return MAX_SCHEDULE_TIMEOUT - 1;
> +
> +       return timeout_jiffies;
> +}
> +
> +static int drm_syncobj_wait_all_fences(struct drm_device *dev,
> +                                      struct drm_file *file_private,
> +                                      struct drm_syncobj_wait *wait,
> +                                      uint32_t *handles)
> +{
> +       uint32_t i;
> +       int ret;
> +       unsigned long timeout = drm_timeout_abs_to_jiffies(
> wait->timeout_ns);
> +
> +       for (i = 0; i < wait->count_handles; i++) {
> +               struct dma_fence *fence;
> +
> +               ret = drm_syncobj_fence_get(file_private, handles[i],
> +                                           &fence);
> +               if (ret)
> +                       return ret;
> +
> +               if (!fence)
> +                       continue;
> +
> +               ret = dma_fence_wait_timeout(fence, true, timeout);
> +
> +               dma_fence_put(fence);
> +               if (ret < 0)
> +                       return ret;
> +               if (ret == 0)
> +                       break;
> +               timeout = ret;
> +       }
> +
> +       wait->out_timeout_ns = jiffies_to_nsecs(ret);
> +       wait->out_status = (ret > 0);
> +       wait->first_signaled = 0;
> +       return 0;
> +}
> +
> +static int drm_syncobj_wait_any_fence(struct drm_device *dev,
> +                                     struct drm_file *file_private,
> +                                     struct drm_syncobj_wait *wait,
> +                                     uint32_t *handles)
> +{
> +       unsigned long timeout = drm_timeout_abs_to_jiffies(
> wait->timeout_ns);
> +       struct dma_fence **array;
> +       uint32_t i;
> +       int ret;
> +       uint32_t first = ~0;
> +
> +       /* Prepare the fence array */
> +       array = kcalloc(wait->count_handles,
> +                       sizeof(struct dma_fence *), GFP_KERNEL);
> +
> +       if (array == NULL)
> +               return -ENOMEM;
> +
> +       for (i = 0; i < wait->count_handles; i++) {
> +               struct dma_fence *fence;
> +
> +               ret = drm_syncobj_fence_get(file_private, handles[i],
> +                                           &fence);
> +               if (ret)
> +                       goto err_free_fence_array;
> +               else if (fence)
> +                       array[i] = fence;
> +               else { /* NULL, the fence has been already signaled */
> +                       ret = 1;
> +                       goto out;
> +               }
> +       }
> +
> +       ret = dma_fence_wait_any_timeout(array, wait->count_handles,
> true, timeout,
> +                                        &first);
> +       if (ret < 0)
> +               goto err_free_fence_array;
> +out:
> +       wait->out_timeout_ns = jiffies_to_nsecs(ret);
> +       wait->out_status = (ret > 0);
> +       wait->first_signaled = first;
> +       /* set return value 0 to indicate success */
> +       ret = 0;
> +
> +err_free_fence_array:
> +       for (i = 0; i < wait->count_handles; i++)
> +               dma_fence_put(array[i]);
> +       kfree(array);
> +
> +       return ret;
> +}
> +
> +int
> +drm_syncobj_wait_ioctl(struct drm_device *dev, void *data,
> +                      struct drm_file *file_private)
> +{
> +       struct drm_syncobj_wait *args = data;
> +       uint32_t *handles;
> +       int ret = 0;
> +
> +       if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
> +               return -ENODEV;
> +
> +       if (args->flags != 0 && args->flags != DRM_SYNCOBJ_WAIT_FLAGS_WAIT_
> ALL)
> +               return -EINVAL;
> +
> +       if (args->count_handles == 0)
> +               return 0;
> +
> +       /* Get the handles from userspace */
> +       handles = kmalloc_array(args->count_handles, sizeof(uint32_t),
> +                               GFP_KERNEL);
> +       if (handles == NULL)
> +               return -ENOMEM;
> +
> +       if (copy_from_user(handles,
> +                          (void __user *)(unsigned long)(args->handles),
> +                          sizeof(uint32_t) * args->count_handles)) {
> +               ret = -EFAULT;
> +               goto err_free_handles;
> +       }
> +
> +       if (args->flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL)
> +               ret = drm_syncobj_wait_all_fences(dev, file_private,
> +                                                 args, handles);
> +       else
> +               ret = drm_syncobj_wait_any_fence(dev, file_private,
> +                                                args, handles);
> +err_free_handles:
> +       kfree(handles);
> +
> +       return ret;
> +}
> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> index 96c5c78..d6e2f62 100644
> --- a/include/uapi/drm/drm.h
> +++ b/include/uapi/drm/drm.h
> @@ -716,6 +716,19 @@ struct drm_syncobj_handle {
>         __u32 pad;
>  };
>
> +#define DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL (1 << 0)
> +struct drm_syncobj_wait {
> +       __u64 handles;
> +       /* absolute timeout */
> +       __u64 timeout_ns;
> +       /* remaining timeout */
> +       __u64 out_timeout_ns;
>

Any particular reason why we don't just make timeout_ns an in/out?  I don't
really care and haven't given it much thought; mostly just curious.


> +       __u32 count_handles;
> +       __u32 flags;
> +       __u32 out_status;
> +       __u32 first_signaled; /* on valid when not waiting all */
> +};
> +
>  #if defined(__cplusplus)
>  }
>  #endif
> @@ -838,6 +851,7 @@ extern "C" {
>  #define DRM_IOCTL_SYNCOBJ_DESTROY      DRM_IOWR(0xC0, struct
> drm_syncobj_destroy)
>  #define DRM_IOCTL_SYNCOBJ_HANDLE_TO_FD DRM_IOWR(0xC1, struct
> drm_syncobj_handle)
>  #define DRM_IOCTL_SYNCOBJ_FD_TO_HANDLE DRM_IOWR(0xC2, struct
> drm_syncobj_handle)
> +#define DRM_IOCTL_SYNCOBJ_WAIT         DRM_IOWR(0xC3, struct
> drm_syncobj_wait)
>
>  /**
>   * Device specific ioctls should only be in their respective headers
> --
> 2.9.4
>
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>
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