media: v4l: subdev: Return NULL from pad access functions on error

Return NULL from sub-device pad state access functions
(v4l2_subdev_state_get_{format,crop,compose}) for non-existent pads. While
this behaviour differs from older set of pad state information access
functions, we've had a WARN_ON() there for a long time and callers also do
validate the pad index nowadays. Therefore problems are not expected.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 41fe9fa5c21a13dbe11e479ffa0529e8d37cce8c..985873b7981ee32a429aaee4024f0dab048a4e98 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -1545,16 +1545,8 @@ __v4l2_subdev_state_get_format(struct v4l2_subdev_state *state,
                if (stream)
                        return NULL;
 
-               /*
-                * Set the pad to 0 on error as this is aligned with the
-                * behaviour of the pad state information access functions. The
-                * purpose of setting pad to 0 here is to avoid accessing memory
-                * outside the pads array, but still issuing warning of the
-                * invalid access while making the caller's error handling
-                * easier.
-                */
-               if (WARN_ON_ONCE(pad >= state->sd->entity.num_pads))
-                       pad = 0;
+               if (pad >= state->sd->entity.num_pads)
+                       return NULL;
 
                return &state->pads[pad].format;
        }
@@ -1587,16 +1579,8 @@ __v4l2_subdev_state_get_crop(struct v4l2_subdev_state *state, unsigned int pad,
                if (stream)
                        return NULL;
 
-               /*
-                * Set the pad to 0 on error as this is aligned with the
-                * behaviour of the pad state information access functions. The
-                * purpose of setting pad to 0 here is to avoid accessing memory
-                * outside the pads array, but still issuing warning of the
-                * invalid access while making the caller's error handling
-                * easier.
-                */
-               if (WARN_ON_ONCE(pad >= state->sd->entity.num_pads))
-                       pad = 0;
+               if (pad >= state->sd->entity.num_pads)
+                       return NULL;
 
                return &state->pads[pad].crop;
        }
@@ -1629,16 +1613,8 @@ __v4l2_subdev_state_get_compose(struct v4l2_subdev_state *state,
                if (stream)
                        return NULL;
 
-               /*
-                * Set the pad to 0 on error as this is aligned with the
-                * behaviour of the pad state information access functions. The
-                * purpose of setting pad to 0 here is to avoid accessing memory
-                * outside the pads array, but still issuing warning of the
-                * invalid access while making the caller's error handling
-                * easier.
-                */
-               if (WARN_ON_ONCE(pad >= state->sd->entity.num_pads))
-                       pad = 0;
+               if (pad >= state->sd->entity.num_pads)
+                       return NULL;
 
                return &state->pads[pad].compose;
        }