media: iris: Document difference in size during allocation

As we get ready for kzalloc checking for invalid sizes, let's add
documentation for the cases where the size is different but valid.

This patch fixes this cocci warning:
./platform/qcom/iris/iris_hfi_gen2_command.c:1215:9-25: WARNING: casting value returned by memory allocation function to (struct iris_inst *) is useless.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Bryan O'Donoghue <bod@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
index c75c8b9398a20dca32a244e0e2ff03b5bed6ccd2..df31f452b69bb942c979475a0f628a11b84e12b0 100644 (file)
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
@@ -1296,5 +1296,10 @@ void iris_hfi_gen2_command_ops_init(struct iris_core *core)
 
 struct iris_inst *iris_hfi_gen2_get_instance(void)
 {
-       return (struct iris_inst *)kzalloc(sizeof(struct iris_inst_hfi_gen2), GFP_KERNEL);
+       struct iris_inst_hfi_gen2 *out;
+
+       /* The allocation is intentionally larger than struct iris_inst. */
+       out = kzalloc(sizeof(*out), GFP_KERNEL);
+
+       return &out->inst;
 }