Re: [PATCH v3 net 4/4] ixgbevf: Fix passing 0 to ERR_PTR in ixgbevf_run_xdp()

[Maciej Fijalkowski <maciej.fijalkowski@intel.com>]

On Tue, Oct 22, 2024 at 02:56:23PM +0800, Yue Haibing wrote:
> ixgbevf_run_xdp() converts customed xdp action to a negative error code
> with the sk_buff pointer type which be checked with IS_ERR in
> ixgbevf_clean_rx_irq(). Remove this error pointer handing instead use
> plain int return value.
> 
> Fixes: c7aec59657b6 ("ixgbevf: Add XDP support for pass and drop actions")
> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
> Signed-off-by: Yue Haibing <yuehaibing@huawei.com>

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

> ---
>  .../net/ethernet/intel/ixgbevf/ixgbevf_main.c | 23 ++++++++-----------
>  1 file changed, 10 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> index 149911e3002a..183d2305d058 100644
> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> @@ -732,10 +732,6 @@ static bool ixgbevf_cleanup_headers(struct ixgbevf_ring *rx_ring,
>  				    union ixgbe_adv_rx_desc *rx_desc,
>  				    struct sk_buff *skb)
>  {
> -	/* XDP packets use error pointer so abort at this point */
> -	if (IS_ERR(skb))
> -		return true;
> -
>  	/* verify that the packet does not have any known errors */
>  	if (unlikely(ixgbevf_test_staterr(rx_desc,
>  					  IXGBE_RXDADV_ERR_FRAME_ERR_MASK))) {
> @@ -1044,9 +1040,9 @@ static int ixgbevf_xmit_xdp_ring(struct ixgbevf_ring *ring,
>  	return IXGBEVF_XDP_TX;
>  }
>  
> -static struct sk_buff *ixgbevf_run_xdp(struct ixgbevf_adapter *adapter,
> -				       struct ixgbevf_ring  *rx_ring,
> -				       struct xdp_buff *xdp)
> +static int ixgbevf_run_xdp(struct ixgbevf_adapter *adapter,
> +			   struct ixgbevf_ring *rx_ring,
> +			   struct xdp_buff *xdp)
>  {
>  	int result = IXGBEVF_XDP_PASS;
>  	struct ixgbevf_ring *xdp_ring;
> @@ -1080,7 +1076,7 @@ static struct sk_buff *ixgbevf_run_xdp(struct ixgbevf_adapter *adapter,
>  		break;
>  	}
>  xdp_out:
> -	return ERR_PTR(-result);
> +	return result;
>  }
>  
>  static unsigned int ixgbevf_rx_frame_truesize(struct ixgbevf_ring *rx_ring,
> @@ -1122,6 +1118,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
>  	struct sk_buff *skb = rx_ring->skb;
>  	bool xdp_xmit = false;
>  	struct xdp_buff xdp;
> +	int xdp_res = 0;
>  
>  	/* Frame size depend on rx_ring setup when PAGE_SIZE=4K */
>  #if (PAGE_SIZE < 8192)
> @@ -1165,11 +1162,11 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
>  			/* At larger PAGE_SIZE, frame_sz depend on len size */
>  			xdp.frame_sz = ixgbevf_rx_frame_truesize(rx_ring, size);
>  #endif
> -			skb = ixgbevf_run_xdp(adapter, rx_ring, &xdp);
> +			xdp_res = ixgbevf_run_xdp(adapter, rx_ring, &xdp);
>  		}
>  
> -		if (IS_ERR(skb)) {
> -			if (PTR_ERR(skb) == -IXGBEVF_XDP_TX) {
> +		if (xdp_res) {
> +			if (xdp_res == IXGBEVF_XDP_TX) {
>  				xdp_xmit = true;
>  				ixgbevf_rx_buffer_flip(rx_ring, rx_buffer,
>  						       size);
> @@ -1189,7 +1186,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
>  		}
>  
>  		/* exit if we failed to retrieve a buffer */
> -		if (!skb) {
> +		if (!xdp_res && !skb) {
>  			rx_ring->rx_stats.alloc_rx_buff_failed++;
>  			rx_buffer->pagecnt_bias++;
>  			break;
> @@ -1203,7 +1200,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
>  			continue;
>  
>  		/* verify the packet layout is correct */
> -		if (ixgbevf_cleanup_headers(rx_ring, rx_desc, skb)) {
> +		if (xdp_res || ixgbevf_cleanup_headers(rx_ring, rx_desc, skb)) {
>  			skb = NULL;
>  			continue;
>  		}
> -- 
> 2.34.1
>