drm/rockchip/rockchip_drm_gem.c: convert to use vm_map_pages()

Convert to use vm_map_pages() to map range of kernel memory to user vma.

Tested on Rockchip hardware and display is working, including talking to
Lima via prime.

Link: http://lkml.kernel.org/r/7ba359eb1aceac388d05983c1f29b915bdf291f9.1552921225.git.jrdr.linux@gmail.comSigned-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Cc: Pawel Osciak <pawel@osciak.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpu/drm/rockchip/rockchip_drm_gem.c

@@ -221,26 +221,13 @@ static int rockchip_drm_gem_object_mmap_iommu(struct drm_gem_object *obj,
 					      struct vm_area_struct *vma)
 {
 	struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
-	unsigned int i, count = obj->size >> PAGE_SHIFT;
+	unsigned int count = obj->size >> PAGE_SHIFT;
 	unsigned long user_count = vma_pages(vma);
-	unsigned long uaddr = vma->vm_start;
-	unsigned long offset = vma->vm_pgoff;
-	unsigned long end = user_count + offset;
-	int ret;
 
 	if (user_count == 0)
 		return -ENXIO;
-	if (end > count)
-		return -ENXIO;
 
-	for (i = offset; i < end; i++) {
-		ret = vm_insert_page(vma, uaddr, rk_obj->pages[i]);
-		if (ret)
-			return ret;
-		uaddr += PAGE_SIZE;
-	}
-
-	return 0;
+	return vm_map_pages(vma, rk_obj->pages, count);
 }
 
 static int rockchip_drm_gem_object_mmap_dma(struct drm_gem_object *obj,