On Thu, 17 Apr 2025 10:53:23 +0100
Matthew Auld <matthew.a...@intel.com> wrote:
> On 17/04/2025 10:32, Boris Brezillon wrote:
> > Right now the DRM_PANTHOR_BO_NO_MMAP flag is ignored by
> > panthor_ioctl_bo_mmap_offset(), meaning BOs with this flag set can
> > have a file offset but can't be mapped anyway, because
> > panthor_gem_mmap() will filter them out.
> >
> > If we error out at mmap_offset creation time, we can get rid of
> > panthor_gem_mmap() and call drm_gem_shmem_object_mmap directly, and
> > we get rid of this inconsistency of having an mmap offset for a
> > BO that can never be mmap-ed.
> >
> > Changes in v2:
> > - Get rid of panthor_gem_mmap()
> > - Get rid of the Fixes tag and adjust the commit message accordingly
> > - Return ENOPERM instead of EINVAL
> >
> > Signed-off-by: Boris Brezillon <boris.brezil...@collabora.com>
> > ---
> > drivers/gpu/drm/panthor/panthor_drv.c | 5 +++++
> > drivers/gpu/drm/panthor/panthor_gem.c | 13 +------------
> > 2 files changed, 6 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/panthor/panthor_drv.c
> > b/drivers/gpu/drm/panthor/panthor_drv.c
> > index 06fe46e32073..7cd131af340d 100644
> > --- a/drivers/gpu/drm/panthor/panthor_drv.c
> > +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> > @@ -940,6 +940,7 @@ static int panthor_ioctl_bo_mmap_offset(struct
> > drm_device *ddev, void *data,
> > struct drm_file *file)
> > {
> > struct drm_panthor_bo_mmap_offset *args = data;
> > + struct panthor_gem_object *bo;
> > struct drm_gem_object *obj;
> > int ret;
> >
> > @@ -950,6 +951,10 @@ static int panthor_ioctl_bo_mmap_offset(struct
> > drm_device *ddev, void *data,
> > if (!obj)
> > return -ENOENT;
> >
> > + bo = to_panthor_bo(obj);
> > + if (bo->flags & DRM_PANTHOR_BO_NO_MMAP)
> > + return -EPERM;
>
> Just a drive-by-comment: are we not leaking the bo ref here?
We certainly are, good catch!
>
> > +
> > ret = drm_gem_create_mmap_offset(obj);
> > if (ret)
> > goto out;
> > diff --git a/drivers/gpu/drm/panthor/panthor_gem.c
> > b/drivers/gpu/drm/panthor/panthor_gem.c
> > index fd014ccc3bfc..22d78cef9c66 100644
> > --- a/drivers/gpu/drm/panthor/panthor_gem.c
> > +++ b/drivers/gpu/drm/panthor/panthor_gem.c
> > @@ -129,17 +129,6 @@ panthor_kernel_bo_create(struct panthor_device *ptdev,
> > struct panthor_vm *vm,
> > return ERR_PTR(ret);
> > }
> >
> > -static int panthor_gem_mmap(struct drm_gem_object *obj, struct
> > vm_area_struct *vma)
> > -{
> > - struct panthor_gem_object *bo = to_panthor_bo(obj);
> > -
> > - /* Don't allow mmap on objects that have the NO_MMAP flag set. */
> > - if (bo->flags & DRM_PANTHOR_BO_NO_MMAP)
> > - return -EINVAL;
> > -
> > - return drm_gem_shmem_object_mmap(obj, vma);
> > -}
> > -
> > static struct dma_buf *
> > panthor_gem_prime_export(struct drm_gem_object *obj, int flags)
> > {
> > @@ -169,7 +158,7 @@ static const struct drm_gem_object_funcs
> > panthor_gem_funcs = {
> > .get_sg_table = drm_gem_shmem_object_get_sg_table,
> > .vmap = drm_gem_shmem_object_vmap,
> > .vunmap = drm_gem_shmem_object_vunmap,
> > - .mmap = panthor_gem_mmap,
> > + .mmap = drm_gem_shmem_object_mmap,
> > .status = panthor_gem_status,
> > .export = panthor_gem_prime_export,
> > .vm_ops = &drm_gem_shmem_vm_ops,
>
