[Intel-xe] [PATCH 5/5] drm/xe: Return the correct error when dma_resv_wait_timeout fails

[Christopher Snowhill]

On Fri, May 26, 2023 at 12:16 PM Souza, Jose <jose.souza at intel.com> wrote:
>
> On Fri, 2023-05-26 at 14:11 +0200, Maarten Lankhorst wrote:
> > We call dma_resv_wait_timeout with MAX_SCHEDULE_TIMEOUT, so it can
> > never return -ETIME. It will however fail if interrupted, so in that
> > case return the error.
> >
> > Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/239
> > ---
> >  drivers/gpu/drm/xe/xe_bo.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> > index 8735facb1cf9..77ba8492bd90 100644
> > --- a/drivers/gpu/drm/xe/xe_bo.c
> > +++ b/drivers/gpu/drm/xe/xe_bo.c
> > @@ -611,8 +611,8 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict,
> >                                                    DMA_RESV_USAGE_BOOKKEEP,
> >                                                    true,
> >                                                    MAX_SCHEDULE_TIMEOUT);
> > -             if (timeout <= 0) {
> > -                     ret = -ETIME;
> > +             if (timeout < 0) {
> > +                     ret = timeout;
> >                       goto out;
>
> 0 means timeout, so what this is doing is allowing a error to be treated a success.
> I understanding that is should never happen with MAX_SCHEDULE_TIMEOUT but I would rather leave this as "<=" just in case there is a bug in
> dma_resv_wait_timeout() that ignores the MAX_SCHEDULE_TIMEOUT.

If 0 means timeout, and < 0 means other error, then perhaps it should
return -ETIME for 0, otherwise pass on the error?

>
> >               }
> >               ttm_bo_move_null(ttm_bo, new_mem);
>