[Mesa-dev] [PATCH 06/10] panfrost: Avoid passing winsys handles to import/export BO funcs

[Alyssa Rosenzweig]

Question: Does this allow us to map arbitrary CPU buffers into GPU
space? Stuff with no relation to the winsys, just... arbitrary user
memory? That might be useful for index/vertex buffers (which we
currently are forced to memcpy() into a BO we create if given a user
pointer rather than a resource), but maybe not actually because of sync
requirements.

On Tue, Jul 02, 2019 at 03:23:49PM +0200, Boris Brezillon wrote:
> Let's keep a clear split between ioctl wrappers and the rest of the
> driver. All the import BO function need is a dmabuf FD and the screen
> object, and the export one should only take care of generating a dmabuf
> FD out of a BO object. Winsys handle manipulation should stay in the
> resource.c file.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>
> ---
>  src/gallium/drivers/panfrost/pan_drm.c      | 17 +++++++----------
>  src/gallium/drivers/panfrost/pan_resource.c | 16 +++++++++++-----
>  src/gallium/drivers/panfrost/pan_screen.h   |  6 ++----
>  3 files changed, 20 insertions(+), 19 deletions(-)
> 
> diff --git a/src/gallium/drivers/panfrost/pan_drm.c b/src/gallium/drivers/panfrost/pan_drm.c
> index f17f56bc6307..b88ab0e5ce2b 100644
> --- a/src/gallium/drivers/panfrost/pan_drm.c
> +++ b/src/gallium/drivers/panfrost/pan_drm.c
> @@ -114,7 +114,7 @@ panfrost_drm_free_slab(struct panfrost_screen *screen, struct panfrost_memory *m
>  }
>  
>  struct panfrost_bo *
> -panfrost_drm_import_bo(struct panfrost_screen *screen, struct winsys_handle *whandle)
> +panfrost_drm_import_bo(struct panfrost_screen *screen, int fd)
>  {
>  	struct panfrost_bo *bo = rzalloc(screen, struct panfrost_bo);
>          struct drm_panfrost_get_bo_offset get_bo_offset = {0,};
> @@ -122,7 +122,7 @@ panfrost_drm_import_bo(struct panfrost_screen *screen, struct winsys_handle *wha
>          int ret;
>          unsigned gem_handle;
>  
> -	ret = drmPrimeFDToHandle(screen->fd, whandle->handle, &gem_handle);
> +	ret = drmPrimeFDToHandle(screen->fd, fd, &gem_handle);
>  	assert(!ret);
>  
>  	get_bo_offset.handle = gem_handle;
> @@ -141,7 +141,7 @@ panfrost_drm_import_bo(struct panfrost_screen *screen, struct winsys_handle *wha
>  		assert(0);
>  	}
>  
> -        bo->size = lseek(whandle->handle, 0, SEEK_END);
> +        bo->size = lseek(fd, 0, SEEK_END);
>          assert(bo->size > 0);
>          bo->cpu = os_mmap(NULL, bo->size, PROT_READ | PROT_WRITE, MAP_SHARED,
>                         screen->fd, mmap_bo.offset);
> @@ -158,21 +158,18 @@ panfrost_drm_import_bo(struct panfrost_screen *screen, struct winsys_handle *wha
>  }
>  
>  int
> -panfrost_drm_export_bo(struct panfrost_screen *screen, int gem_handle, unsigned int stride, struct winsys_handle *whandle)
> +panfrost_drm_export_bo(struct panfrost_screen *screen, const struct panfrost_bo *bo)
>  {
>          struct drm_prime_handle args = {
> -                .handle = gem_handle,
> +                .handle = bo->gem_handle,
>                  .flags = DRM_CLOEXEC,
>          };
>  
>          int ret = drmIoctl(screen->fd, DRM_IOCTL_PRIME_HANDLE_TO_FD, &args);
>          if (ret == -1)
> -                return FALSE;
> +                return -1;
>  
> -        whandle->handle = args.fd;
> -        whandle->stride = stride;
> -
> -        return TRUE;
> +        return args.fd;
>  }
>  
>  static int
> diff --git a/src/gallium/drivers/panfrost/pan_resource.c b/src/gallium/drivers/panfrost/pan_resource.c
> index 8901aeee09b1..f86617f80c20 100644
> --- a/src/gallium/drivers/panfrost/pan_resource.c
> +++ b/src/gallium/drivers/panfrost/pan_resource.c
> @@ -70,7 +70,7 @@ panfrost_resource_from_handle(struct pipe_screen *pscreen,
>          pipe_reference_init(&prsc->reference, 1);
>          prsc->screen = pscreen;
>  
> -	rsc->bo = panfrost_drm_import_bo(screen, whandle);
> +	rsc->bo = panfrost_drm_import_bo(screen, whandle->handle);
>  	rsc->slices[0].stride = whandle->stride;
>  	rsc->slices[0].initialized = true;
>  
> @@ -120,10 +120,16 @@ panfrost_resource_get_handle(struct pipe_screen *pscreen,
>                          handle->handle = args.fd;
>  
>                          return TRUE;
> -                } else
> -			return panfrost_drm_export_bo(screen, rsrc->bo->gem_handle,
> -                                                      rsrc->slices[0].stride,
> -                                                      handle);
> +                } else {
> +                        int fd = panfrost_drm_export_bo(screen, rsrc->bo);
> +
> +                        if (fd < 0)
> +                                return FALSE;
> +
> +                        handle->handle = fd;
> +                        handle->stride = rsrc->slices[0].stride;
> +                        return TRUE;
> +		}
>  	}
>  
>  	return FALSE;
> diff --git a/src/gallium/drivers/panfrost/pan_screen.h b/src/gallium/drivers/panfrost/pan_screen.h
> index 83186ebb2f7f..1a1eb2f8bf27 100644
> --- a/src/gallium/drivers/panfrost/pan_screen.h
> +++ b/src/gallium/drivers/panfrost/pan_screen.h
> @@ -83,11 +83,9 @@ void
>  panfrost_drm_free_slab(struct panfrost_screen *screen,
>                         struct panfrost_memory *mem);
>  struct panfrost_bo *
> -panfrost_drm_import_bo(struct panfrost_screen *screen,
> -                       struct winsys_handle *whandle);
> +panfrost_drm_import_bo(struct panfrost_screen *screen, int fd);
>  int
> -panfrost_drm_export_bo(struct panfrost_screen *screen, int gem_handle,
> -                       unsigned int stride, struct winsys_handle *whandle);
> +panfrost_drm_export_bo(struct panfrost_screen *screen, const struct panfrost_bo *bo);
>  int
>  panfrost_drm_submit_vs_fs_job(struct panfrost_context *ctx, bool has_draws,
>                                bool is_scanout);
> -- 
> 2.21.0
> 
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