On Fri, Jun 19, 2015 at 02:52:28PM +0100, Daniel Thompson wrote: > Currently DRM_IOCTL_PRIME_HANDLE_TO_FD rejects all flags except > (DRM|O)_CLOEXEC making it difficult (maybe impossible) for userspace > to mmap() the resulting dma-buf even when this is supported by the > DRM driver. > > It is trivial to relax the restriction and permit read/write access. > This is safe because the flags are seldom touched by drm; mostly they > are passed verbatim to dma_buf calls. > > Signed-off-by: Daniel Thompson <daniel.thomp...@linaro.org> > --- > drivers/gpu/drm/drm_prime.c | 9 +++------ > include/uapi/drm/drm.h | 1 + > 2 files changed, 4 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c > index 7fec191b45f7..6d2cf4fb4038 100644 > --- a/drivers/gpu/drm/drm_prime.c > +++ b/drivers/gpu/drm/drm_prime.c > @@ -331,7 +331,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops > = { > * drm_gem_prime_export - helper library implementation of the export > callback > * @dev: drm_device to export from > * @obj: GEM object to export > - * @flags: flags like DRM_CLOEXEC > + * @flags: flags like DRM_CLOEXEC and DRM_RDWR > * > * This is the implementation of the gem_prime_export functions for GEM > drivers > * using the PRIME helpers. > @@ -639,14 +639,11 @@ int drm_prime_handle_to_fd_ioctl(struct drm_device > *dev, void *data, > return -ENOSYS; > > /* check flags are valid */ > - if (args->flags & ~DRM_CLOEXEC) > + if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR)) > return -EINVAL;
I think we should reject DRM_RDWR if there's no mmap implementation in the underlying dma-buf vfunc table. Or in the gem version of those. Otherwise looks ok to me, if we first resolve the dma-buf userspace mmap coherency issue. -Daniel > > - /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */ > - flags = args->flags & DRM_CLOEXEC; > - > return dev->driver->prime_handle_to_fd(dev, file_priv, > - args->handle, flags, &args->fd); > + args->handle, args->flags, &args->fd); > } > > int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data, > diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h > index ff6ef62d084b..092fe3fa8ec0 100644 > --- a/include/uapi/drm/drm.h > +++ b/include/uapi/drm/drm.h > @@ -668,6 +668,7 @@ struct drm_set_client_cap { > __u64 value; > }; > > +#define DRM_RDWR O_RDWR > #define DRM_CLOEXEC O_CLOEXEC > struct drm_prime_handle { > __u32 handle; > -- > 2.4.3 > > _______________________________________________ > dri-devel mailing list > dri-de...@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/