drm/i915: Implement dma_buf_ops->kmap
Since kmap allows us to block we can pin the pages and use our normal
page lookup routine making the implementation simple, or as some might
say quick and dirty.
Testcase: igt/drv_selftest/dmabuf
Testcase: igt/prime_rw
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170503202517.16797-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index f225bf6..6176e58 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -122,12 +122,36 @@ static void i915_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf, unsigned long
}
static void *i915_gem_dmabuf_kmap(struct dma_buf *dma_buf, unsigned long page_num)
{
+ struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+ struct page *page;
+
+ if (page_num >= obj->base.size >> PAGE_SHIFT)
+ return NULL;
+
+ if (!i915_gem_object_has_struct_page(obj))
+ return NULL;
+
+ if (i915_gem_object_pin_pages(obj))
+ return NULL;
+
+ /* Synchronisation is left to the caller (via .begin_cpu_access()) */
+ page = i915_gem_object_get_page(obj, page_num);
+ if (IS_ERR(page))
+ goto err_unpin;
+
+ return kmap(page);
+
+err_unpin:
+ i915_gem_object_unpin_pages(obj);
return NULL;
}
static void i915_gem_dmabuf_kunmap(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
{
+ struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+ kunmap(virt_to_page(addr));
+ i915_gem_object_unpin_pages(obj);
}
static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)