zink: super reorder buffer copies

usually zink_get_cmdbuf() is enough for reordering operations, but
with new technology, it becomes possible to promote even the most stubborn
buffers to the unordered cmdbuf

first, check the src buffer to ensure that there's no pending writes in
the main cmdbuf that would prohibit reordering

second, apply a TRANSFER_DST to the dst buffer using the util function
to determine whether it can be reordered

if both the src and dst can be reordered for their respective regions
and read/write usage, then the entire op can be promoted regardless of
the unordered_read/unordered_write flags

this optimizes out patterns like
upload index buffer (offset=0)
draw
upload index buffer (offset=128)
draw
upload index buffer (offset=256)
draw
...

so that the uploads and draws can be separated and batched

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21802>

src/gallium/drivers/zink/zink_context.c

@@ -4680,9 +4680,16 @@ zink_copy_buffer(struct zink_context *ctx, struct zink_resource *dst, struct zin
    region.size = size;
 
    struct zink_batch *batch = &ctx->batch;
+
+   struct pipe_box box = {src_offset, 0, 0, size, 0, 0};
+   /* must barrier if something wrote the valid buffer range */
+   bool valid_write = src->obj->access && util_ranges_intersect(&src->valid_buffer_range, src_offset, src_offset + size) && !unordered_res_exec(ctx, src, false);
+   bool unordered_src = !valid_write && !zink_check_unordered_transfer_access(src, 0, &box);
    zink_screen(ctx->base.screen)->buffer_barrier(ctx, src, VK_ACCESS_TRANSFER_READ_BIT, 0);
-   zink_resource_buffer_transfer_dst_barrier(ctx, dst, dst_offset, size);
-   VkCommandBuffer cmdbuf = zink_get_cmdbuf(ctx, src, dst);
+   bool unordered_dst = zink_resource_buffer_transfer_dst_barrier(ctx, dst, dst_offset, size);
+   bool can_unorder = unordered_dst && unordered_src && !(zink_debug & ZINK_DEBUG_NOREORDER);
+   VkCommandBuffer cmdbuf = can_unorder ? ctx->batch.state->barrier_cmdbuf : zink_get_cmdbuf(ctx, src, dst);
+   ctx->batch.state->has_barriers |= can_unorder;
    zink_batch_reference_resource_rw(batch, src, false);
    zink_batch_reference_resource_rw(batch, dst, true);
    VKCTX(CmdCopyBuffer)(cmdbuf, src->obj->buffer, dst->obj->buffer, 1, &region);