For a fault at address addr, the page offset is page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT = ((addr & PAGE_MASK) - vma->vm_start) >> PAGE_SHIFT = (addr - vma->vm_start) >> PAGE_SHIFT Since the faulty logical page offset based on VMA is vmf->pgoff = vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) We can slightly simplify the calculation using page_offset = vmf->pgoff - vma->vm_pgoff Signed-off-by: Loïc Molinari --- drivers/gpu/drm/drm_gem_shmem_helper.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index dc94a27710e5..be89be1c804c 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -577,8 +577,8 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) struct page *page; pgoff_t page_offset; - /* We don't use vmf->pgoff since that has the fake offset */ - page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT; + /* Offset to faulty address in the VMA (without the fake offset). */ + page_offset = vmf->pgoff - vma->vm_pgoff; dma_resv_lock(shmem->base.resv, NULL); -- 2.47.3