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>
---
 drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

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 f9129553209922fda548ca320494ae6ae797854c..c120ea3594fb5d0f40d6b9a7c67ffc28c42109f0 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
@@ -1212,5 +1212,10 @@ 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;
 }

-- 
2.52.0.358.g0dd7633a29-goog

On 23/12/2025 10:02, Ricardo Ribalda wrote:
> 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>
> ---
>   drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> 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 f9129553209922fda548ca320494ae6ae797854c..c120ea3594fb5d0f40d6b9a7c67ffc28c42109f0 100644
> --- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
> +++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
> @@ -1212,5 +1212,10 @@ 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;
>   }
> 
> --
> 2.52.0.358.g0dd7633a29-goog
> 
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

---
bod