winsys/amdgpu: explicitly declare whether buffer_map is permanent or not

Introduce a new driver-private transfer flag RADEON_TRANSFER_TEMPORARY
that specifies whether the caller will use buffer_unmap or not. The
default behavior is set to permanent maps, because that's what drivers
do for Gallium buffer maps.

This should eliminate the need for hacks in libdrm. Assertions are added
to catch when the buffer_unmap calls don't match the (temporary)
buffer_map calls.

I did my best to update r600 for consistency (r300 needs no changes
because it never calls buffer_unmap), even though the radeon winsys
ignores the new flag.

As an added bonus, this should actually improve the performance of
the normal fast path, because we no longer call into libdrm at all
after the first map, and there's one less atomic in the winsys itself
(there are now no atomics left in the UNSYNCHRONIZED fast path).

Cc: Leo Liu <leo.liu@amd.com>
v2:
- remove comment about visible VRAM (Marek)
- don't rely on amdgpu_bo_cpu_map doing an atomic write
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.h b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.h
index 58e6eed733d..88f4241327d 100644
--- a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.h
+++ b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.h
@@ -88,10 +88,11 @@ struct amdgpu_winsys_bo {
    } u;
 
    struct amdgpu_winsys *ws;
-   void *user_ptr; /* from buffer_from_ptr */
+   void *cpu_ptr; /* for user_ptr and permanent maps */
 
    amdgpu_bo_handle bo; /* NULL for slab entries and sparse buffers */
    bool sparse;
+   bool is_user_ptr;
    bool is_local;
    uint32_t unique_id;
    uint64_t va;