Assign vmap, vunmap and mmap fields in dma_buf_ops structs only
if kernel version >= 3.5.0 as they are added in 3.5. The begin_cpu_access
was added as of the original dma-buf code via 3.4.

mcgrof@frijol ~/linux-next (git::master)$ git describe --contains fc13020e086bfedf2afb95c91c026d5af1f80107
v3.4-rc1~57^2~3

Note that the dma-buf itself was added with 3.4. It is not available
on kernels < 3.4. 

--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -216,10 +216,14 @@ static const struct dma_buf_ops i915_dma
 	.kmap_atomic = i915_gem_dmabuf_kmap_atomic,
 	.kunmap = i915_gem_dmabuf_kunmap,
 	.kunmap_atomic = i915_gem_dmabuf_kunmap_atomic,
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,5,0))
 	.mmap = i915_gem_dmabuf_mmap,
 	.vmap = i915_gem_dmabuf_vmap,
 	.vunmap = i915_gem_dmabuf_vunmap,
+#endif
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0))
 	.begin_cpu_access = i915_gem_begin_cpu_access,
+#endif
 };
 
 struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -152,9 +152,11 @@ static const struct dma_buf_ops drm_gem_
 	.kmap_atomic = drm_gem_dmabuf_kmap_atomic,
 	.kunmap = drm_gem_dmabuf_kunmap,
 	.kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,5,0))
 	.mmap = drm_gem_dmabuf_mmap,
 	.vmap = drm_gem_dmabuf_vmap,
 	.vunmap = drm_gem_dmabuf_vunmap,
+#endif
 };
 
 /**