On Tue, 22 Sep 2026 11:07:43 +0100
Akash Goel <[email protected]> wrote:
> The BOs created with DRM_PANTHOR_BO_NO_MMAP flag are not supposed to be
> mmappable by the Userspace. But after the rework to support shrinker,
> it became possible to mmap NO_MMAP BOs. Userspace could second guess
> the file offset range, allocated unconditionally at the BO creation
> time, and create a CPU mapping. There may not be any adverse effect of
> such a CPU mapping though.
> This commit removes the unconditional allocation of file offset range
> when a user/kernel BO is created. For user BOs, allocation of file
> offset range would be done from BO_MMAP_OFFSET ioctl handler which has
> a check for NO_MMAP flag. For kernel BOs, there is no need to allocate
> file offset range.
>
> Fixes: 68cbf96b1e9b ("drm/panthor: Part ways with drm_gem_shmem_object")
> Suggested-by: Boris Brezillon <[email protected]>
> Signed-off-by: Akash Goel <[email protected]>
Reviewed-by: Boris Brezillon <[email protected]>
> ---
> drivers/gpu/drm/panthor/panthor_gem.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.c
> b/drivers/gpu/drm/panthor/panthor_gem.c
> index c07a44057e42..5cfe66537e87 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.c
> +++ b/drivers/gpu/drm/panthor/panthor_gem.c
> @@ -1021,10 +1021,6 @@ panthor_gem_create(struct drm_device *dev, size_t
> size, uint32_t flags,
> mapping_set_gfp_mask(bo->base.filp->f_mapping,
> GFP_HIGHUSER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
>
> - ret = drm_gem_create_mmap_offset(&bo->base);
> - if (ret)
> - goto err_put;
> -
> if (exclusive_vm) {
> bo->exclusive_vm_root_gem = panthor_vm_root_gem(exclusive_vm);
> drm_gem_object_get(bo->exclusive_vm_root_gem);
