From 83b8a6f242ea6b4eafe69afcd0bfa428235f2ee4 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Thu, 24 Oct 2019 14:18:59 -0500 Subject: [PATCH] drm/gem: Fix mmap fake offset handling for drm_gem_object_funcs.mmap Commit c40069cb7bd6 ("drm: add mmap() to drm_gem_object_funcs") introduced a GEM object mmap() hook which is expected to subtract the fake offset from vm_pgoff. However, for mmap() on dmabufs, there is not a fake offset. To fix this, let's always call mmap() object callback with an offset of 0, and leave it up to drm_gem_mmap_obj() to remove the fake offset. TTM still needs the fake offset, so we have to add it back until that's fixed. Fixes: c40069cb7bd6 ("drm: add mmap() to drm_gem_object_funcs") Cc: Gerd Hoffmann Cc: Daniel Vetter Signed-off-by: Rob Herring Acked-by: Gerd Hoffmann Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20191024191859.31700-1-robh@kernel.org --- drivers/gpu/drm/drm_gem.c | 3 +++ drivers/gpu/drm/drm_gem_shmem_helper.c | 3 --- drivers/gpu/drm/ttm/ttm_bo_vm.c | 7 +++++++ include/drm/drm_gem.h | 5 +++-- 4 files changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 56f42e0..2f2b889 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -1106,6 +1106,9 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, return -EINVAL; if (obj->funcs && obj->funcs->mmap) { + /* Remove the fake offset */ + vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node); + ret = obj->funcs->mmap(obj, vma); if (ret) return ret; diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 3bc69b1..0810d3e 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -541,9 +541,6 @@ int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma) vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot); vma->vm_ops = &drm_gem_shmem_vm_ops; - /* Remove the fake offset */ - vma->vm_pgoff -= drm_vma_node_start(&shmem->base.vma_node); - return 0; } EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap); diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index f4dd09b..4b34a27 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -480,6 +480,13 @@ EXPORT_SYMBOL(ttm_bo_mmap); int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo) { ttm_bo_get(bo); + + /* + * FIXME: &drm_gem_object_funcs.mmap is called with the fake offset + * removed. Add it back here until the rest of TTM works without it. + */ + vma->vm_pgoff += drm_vma_node_start(&bo->base.vma_node); + ttm_bo_mmap_vma_setup(bo, vma); return 0; } diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h index e71f75a..97a4816 100644 --- a/include/drm/drm_gem.h +++ b/include/drm/drm_gem.h @@ -159,8 +159,9 @@ struct drm_gem_object_funcs { * * The callback is used by by both drm_gem_mmap_obj() and * drm_gem_prime_mmap(). When @mmap is present @vm_ops is not - * used, the @mmap callback must set vma->vm_ops instead. - * + * used, the @mmap callback must set vma->vm_ops instead. The @mmap + * callback is always called with a 0 offset. The caller will remove + * the fake offset as necessary. */ int (*mmap)(struct drm_gem_object *obj, struct vm_area_struct *vma); -- 2.7.4