Re: [PATCH RFT net-next 2/2] idpf: remove __free usage in idpf_virtchnl

[Jeff Johnson <jeff.johnson@oss.qualcomm.com>]

On 11/16/2025 7:56 AM, Ally Heev wrote:
> usage of cleanup attributes is discouraged in net [1], achieve cleanup
> using goto. In this patch though, only uninitialized pointers with __free
> attribute are cleaned as they can cause undefined behavior when they
> go out of scope
> 
> Suggested-by: Simon Horman <horms@kernel.org>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/all/aPiG_F5EBQUjZqsl@stanley.mountain/
> Signed-off-by: Ally Heev <allyheev@gmail.com>
> 
> [1] https://docs.kernel.org/process/maintainer-netdev.html#using-device-managed-and-cleanup-h-constructs

<SMH>

If using __free() *correctly* gives more readable code, why wouldn't we do it?

The only problem with this function is that it doesn't follow the guidance
from cleanup.h:

 * the recommendation is to always define and assign variables in one
 * statement and not group variable definitions at the top of the
 * function when __free() is used.


> 
> Signed-off-by: Ally Heev <allyheev@gmail.com>
> ---
>  drivers/net/ethernet/intel/idpf/idpf_virtchnl.c | 28 +++++++++++++++++--------
>  1 file changed, 19 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> index cbb5fa30f5a0ec778c1ee30470da3ca21cc1af24..5b2bf8c3205bc1ea0746f78afa2a24f3f8ad2a8c 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> @@ -1012,7 +1012,7 @@ static int idpf_send_get_caps_msg(struct idpf_adapter *adapter)
>   */
>  static int idpf_send_get_lan_memory_regions(struct idpf_adapter *adapter)
>  {
> -	struct virtchnl2_get_lan_memory_regions *rcvd_regions __free(kfree);
> +	struct virtchnl2_get_lan_memory_regions *rcvd_regions = NULL;
>  	struct idpf_vc_xn_params xn_params = {
>  		.vc_op = VIRTCHNL2_OP_GET_LAN_MEMORY_REGIONS,
>  		.recv_buf.iov_len = IDPF_CTLQ_MAX_BUF_LEN,
> @@ -1029,21 +1029,29 @@ static int idpf_send_get_lan_memory_regions(struct idpf_adapter *adapter)
>  
>  	xn_params.recv_buf.iov_base = rcvd_regions;
>  	reply_sz = idpf_vc_xn_exec(adapter, &xn_params);
> -	if (reply_sz < 0)
> -		return reply_sz;
> +	if (reply_sz < 0) {
> +		err = reply_sz;
> +		goto out;
> +	}
>  
>  	num_regions = le16_to_cpu(rcvd_regions->num_memory_regions);
>  	size = struct_size(rcvd_regions, mem_reg, num_regions);
> -	if (reply_sz < size)
> -		return -EIO;
> +	if (reply_sz < size) {
> +		err = -EIO;
> +		goto out;
> +	}
>  
> -	if (size > IDPF_CTLQ_MAX_BUF_LEN)
> -		return -EINVAL;
> +	if (size > IDPF_CTLQ_MAX_BUF_LEN) {
> +		err = -EINVAL;
> +		goto out;
> +	}
>  
>  	hw = &adapter->hw;
>  	hw->lan_regs = kcalloc(num_regions, sizeof(*hw->lan_regs), GFP_KERNEL);
> -	if (!hw->lan_regs)
> -		return -ENOMEM;
> +	if (!hw->lan_regs) {
> +		err = -ENOMEM;
> +		goto out;
> +	}
>  
>  	for (int i = 0; i < num_regions; i++) {
>  		hw->lan_regs[i].addr_len =
> @@ -1053,6 +1061,8 @@ static int idpf_send_get_lan_memory_regions(struct idpf_adapter *adapter)
>  	}
>  	hw->num_lan_regs = num_regions;
>  
> +out:
> +	kfree(rcvd_regions);
>  	return err;
>  }
>  
>