[PATCH v2 6/7] drm/rockchip: Respect page offset in IOMMU mmap

[Mark Yao]

From: Ørjan Eide <orjan.eide at arm.com>

When mapping buffers through the PRIME DMA-buf mmap path we might be
given an offset which has to be respected. The DRM GEM mmap path already
takes care of zeroing out the fake mmap offset, so we can just make the
IOMMU mmap implementation always respect the offset.

TEST=graphics_GLBench

Signed-off-by: rjan Eide <orjan.eide at arm.com>
Signed-off-by: Tomasz Figa <tfiga at chromium.org>
Signed-off-by: Mark Yao <mark.yao at rock-chips.com>
Reviewed-on: https://chromium-review.googlesource.com/386477
Reviewed-by: Daniel Kurtz <djkurtz at chromium.org>
---
 drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index 1daa531..1769146 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -221,12 +221,16 @@ static int rockchip_drm_gem_object_mmap_iommu(struct drm_gem_object *obj,
 	unsigned int i, count = obj->size >> PAGE_SHIFT;
 	unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 	unsigned long uaddr = vma->vm_start;
+	unsigned long offset = vma->vm_pgoff;
+	unsigned long end = user_count + offset;
 	int ret;
 
-	if (user_count == 0 || user_count > count)
+	if (user_count == 0)
+		return -ENXIO;
+	if (end > count)
 		return -ENXIO;
 
-	for (i = 0; i < user_count; i++) {
+	for (i = offset; i < end; i++) {
 		ret = vm_insert_page(vma, uaddr, rk_obj->pages[i]);
 		if (ret)
 			return ret;
-- 
1.9.1