Re: [PATCH v3 net 3/4] ixgbe: Fix passing 0 to ERR_PTR in ixgbe_run_xdp()

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

On Tue, Oct 22, 2024 at 02:56:22PM +0800, Yue Haibing wrote:
> ixgbe_run_xdp() converts customed xdp action to a negative error code
> with the sk_buff pointer type which be checked with IS_ERR in
> ixgbe_clean_rx_irq(). Remove this error pointer handing instead use
> plain int return value.
> 
> Fixes: 924708081629 ("ixgbe: 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>

> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 23 ++++++++-----------
>  1 file changed, 9 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index 8b8404d8c946..78bf97ab0524 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -1908,10 +1908,6 @@ bool ixgbe_cleanup_headers(struct ixgbe_ring *rx_ring,
>  {
>  	struct net_device *netdev = rx_ring->netdev;
>  
> -	/* XDP packets use error pointer so abort at this point */
> -	if (IS_ERR(skb))
> -		return true;
> -
>  	/* Verify netdev is present, and that packet does not have any
>  	 * errors that would be unacceptable to the netdev.
>  	 */
> @@ -2219,9 +2215,9 @@ static struct sk_buff *ixgbe_build_skb(struct ixgbe_ring *rx_ring,
>  	return skb;
>  }
>  
> -static struct sk_buff *ixgbe_run_xdp(struct ixgbe_adapter *adapter,
> -				     struct ixgbe_ring *rx_ring,
> -				     struct xdp_buff *xdp)
> +static int ixgbe_run_xdp(struct ixgbe_adapter *adapter,
> +			 struct ixgbe_ring *rx_ring,
> +			 struct xdp_buff *xdp)
>  {
>  	int err, result = IXGBE_XDP_PASS;
>  	struct bpf_prog *xdp_prog;
> @@ -2271,7 +2267,7 @@ static struct sk_buff *ixgbe_run_xdp(struct ixgbe_adapter *adapter,
>  		break;
>  	}
>  xdp_out:
> -	return ERR_PTR(-result);
> +	return result;
>  }
>  
>  static unsigned int ixgbe_rx_frame_truesize(struct ixgbe_ring *rx_ring,
> @@ -2329,6 +2325,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
>  	unsigned int offset = rx_ring->rx_offset;
>  	unsigned int xdp_xmit = 0;
>  	struct xdp_buff xdp;
> +	int xdp_res = 0;
>  
>  	/* Frame size depend on rx_ring setup when PAGE_SIZE=4K */
>  #if (PAGE_SIZE < 8192)
> @@ -2374,12 +2371,10 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
>  			/* At larger PAGE_SIZE, frame_sz depend on len size */
>  			xdp.frame_sz = ixgbe_rx_frame_truesize(rx_ring, size);
>  #endif
> -			skb = ixgbe_run_xdp(adapter, rx_ring, &xdp);
> +			xdp_res = ixgbe_run_xdp(adapter, rx_ring, &xdp);
>  		}
>  
> -		if (IS_ERR(skb)) {
> -			unsigned int xdp_res = -PTR_ERR(skb);
> -
> +		if (xdp_res) {
>  			if (xdp_res & (IXGBE_XDP_TX | IXGBE_XDP_REDIR)) {
>  				xdp_xmit |= xdp_res;
>  				ixgbe_rx_buffer_flip(rx_ring, rx_buffer, size);
> @@ -2399,7 +2394,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_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;
> @@ -2413,7 +2408,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
>  			continue;
>  
>  		/* verify the packet layout is correct */
> -		if (ixgbe_cleanup_headers(rx_ring, rx_desc, skb))
> +		if (xdp_res || ixgbe_cleanup_headers(rx_ring, rx_desc, skb))
>  			continue;
>  
>  		/* probably a little skewed due to removing CRC */
> -- 
> 2.34.1
>