[PATCH] drm/amd/display: fix usage of DC_FPU_{BEGIN,END} with PREEMPT_RT

On PREEMPT_RT kernels kvzalloc_obj() can sleep because spin_lock is
converted to rt_mutex. dc_create_plane_state() can be called while
inside an FPU-guarded region, resuling in "scheduling while atomic"
errors on PREEMPT_RT kernels.
 Fix this by calling kvzalloc_obj() with DC_RUN_WITH_PREEMPTION_ENABLED().
Also fix the error path in dc_create_stream_for_sink().

Fixes: 3539437f354b ("drm/amd/display: Move FPU Guards From DML To DC - Pa=
rt 1")
Link: https://lore.kernel.org/lkml/[email protected]/

Signed-off-by: Bert Karwatzki <[email protected]>
=2D--
 drivers/gpu/drm/amd/display/dc/core/dc_stream.c  | 2 +-
 drivers/gpu/drm/amd/display/dc/core/dc_surface.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c b/drivers/gpu=
/drm/amd/display/dc/core/dc_stream.c
index cdcf140bc1bb..accad9e20e88 100644
=2D-- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
@@ -229,7 +229,7 @@ struct dc_stream_state *dc_create_stream_for_sink(
=20
 fail:
 	if (stream)
-		kfree(stream);
+		DC_RUN_WITH_PREEMPTION_ENABLED(kfree(stream));
=20
 	return NULL;
 }
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_surface.c b/drivers/gp=
u/drm/amd/display/dc/core/dc_surface.c
index 88e825a6582c..d5c6427796b6 100644
=2D-- a/drivers/gpu/drm/amd/display/dc/core/dc_surface.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_surface.c
@@ -85,8 +85,8 @@ uint8_t  dc_plane_get_pipe_mask(struct dc_state *dc_stat=
e, const struct dc_plane
  ************************************************************************=
******/
 struct dc_plane_state *dc_create_plane_state(const struct dc *dc)
 {
-	struct dc_plane_state *plane_state =3D kvzalloc_obj(*plane_state,
-							  GFP_ATOMIC);
+	struct dc_plane_state *plane_state;
+	DC_RUN_WITH_PREEMPTION_ENABLED(plane_state =3D kvzalloc_obj(*plane_state=
, GFP_ATOMIC));
=20
 	if (NULL =3D=3D plane_state)
 		return NULL;
=2D-=20
2.53.0


Rebased to next-20260729+. In these version the allocation of
update_scratch has been removed from dc_create_stream_for_sink().

Bert Karwatzki