Re: [PATCH RFC v2 28/33] xdp: for Intel AF_XDP drivers add XDP frame_sz

[Maxim Mikityanskiy <maximmi@mellanox.com>]

On 2020-04-08 20:31, Björn Töpel wrote:
> On 2020-04-08 13:52, Jesper Dangaard Brouer wrote:
>> Intel drivers implement native AF_XDP zerocopy in separate C-files,
>> that have its own invocation of bpf_prog_run_xdp(). The setup of
>> xdp_buff is also handled in separately from normal code path.
>>
>> This patch update XDP frame_sz for AF_XDP zerocopy drivers i40e, ice
>> and ixgbe, as the code changes needed are very similar.  Introduce a
>> helper function xsk_umem_xdp_frame_sz() for calculating frame size.
>>
>> Cc: intel-wired-lan@lists.osuosl.org
>> Cc: Björn Töpel <bjorn.topel@intel.com>
>> Cc: Magnus Karlsson <magnus.karlsson@intel.com>
>> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> 
> Thanks for the patch, Jesper! Note that mlx5 has AF_XDP support as well,
> and might need similar changes. Adding Max for input!

Thanks for drawing my attention to this series, Björn! I commented 
regarding frame_sz calculation under the mlx5 patch (17/33).

> For the Intel drivers, and core AF_XDP:
> Acked-by: Björn Töpel <bjorn.topel@intel.com>
> 
>> ---
>>   drivers/net/ethernet/intel/i40e/i40e_xsk.c   |    2 ++
>>   drivers/net/ethernet/intel/ice/ice_xsk.c     |    2 ++
>>   drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c |    2 ++
>>   include/net/xdp_sock.h                       |   11 +++++++++++
>>   4 files changed, 17 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c 
>> b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
>> index 0b7d29192b2c..2b9184aead5f 100644
>> --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
>> +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
>> @@ -531,12 +531,14 @@ int i40e_clean_rx_irq_zc(struct i40e_ring 
>> *rx_ring, int budget)
>>   {
>>       unsigned int total_rx_bytes = 0, total_rx_packets = 0;
>>       u16 cleaned_count = I40E_DESC_UNUSED(rx_ring);
>> +    struct xdp_umem *umem = rx_ring->xsk_umem;
>>       unsigned int xdp_res, xdp_xmit = 0;
>>       bool failure = false;
>>       struct sk_buff *skb;
>>       struct xdp_buff xdp;
>>       xdp.rxq = &rx_ring->xdp_rxq;
>> +    xdp.frame_sz = xsk_umem_xdp_frame_sz(umem);
>>       while (likely(total_rx_packets < (unsigned int)budget)) {
>>           struct i40e_rx_buffer *bi;
>> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c 
>> b/drivers/net/ethernet/intel/ice/ice_xsk.c
>> index 8279db15e870..23e5515d4527 100644
>> --- a/drivers/net/ethernet/intel/ice/ice_xsk.c
>> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
>> @@ -840,11 +840,13 @@ int ice_clean_rx_irq_zc(struct ice_ring 
>> *rx_ring, int budget)
>>   {
>>       unsigned int total_rx_bytes = 0, total_rx_packets = 0;
>>       u16 cleaned_count = ICE_DESC_UNUSED(rx_ring);
>> +    struct xdp_umem *umem = rx_ring->xsk_umem;
>>       unsigned int xdp_xmit = 0;
>>       bool failure = false;
>>       struct xdp_buff xdp;
>>       xdp.rxq = &rx_ring->xdp_rxq;
>> +    xdp.frame_sz = xsk_umem_xdp_frame_sz(umem);
>>       while (likely(total_rx_packets < (unsigned int)budget)) {
>>           union ice_32b_rx_flex_desc *rx_desc;
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c 
>> b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
>> index 74b540ebb3dc..a656ee9a1fae 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
>> @@ -431,12 +431,14 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector 
>> *q_vector,
>>       unsigned int total_rx_bytes = 0, total_rx_packets = 0;
>>       struct ixgbe_adapter *adapter = q_vector->adapter;
>>       u16 cleaned_count = ixgbe_desc_unused(rx_ring);
>> +    struct xdp_umem *umem = rx_ring->xsk_umem;
>>       unsigned int xdp_res, xdp_xmit = 0;
>>       bool failure = false;
>>       struct sk_buff *skb;
>>       struct xdp_buff xdp;
>>       xdp.rxq = &rx_ring->xdp_rxq;
>> +    xdp.frame_sz = xsk_umem_xdp_frame_sz(umem);
>>       while (likely(total_rx_packets < budget)) {
>>           union ixgbe_adv_rx_desc *rx_desc;
>> diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
>> index e86ec48ef627..1cd1ec3cea97 100644
>> --- a/include/net/xdp_sock.h
>> +++ b/include/net/xdp_sock.h
>> @@ -237,6 +237,12 @@ static inline u64 xsk_umem_adjust_offset(struct 
>> xdp_umem *umem, u64 address,
>>       else
>>           return address + offset;
>>   }
>> +
>> +static inline u32 xsk_umem_xdp_frame_sz(struct xdp_umem *umem)
>> +{
>> +    return umem->chunk_size_nohr + umem->headroom;
>> +}
>> +

This new function may be used in mlx5 for mlx5e_build_xsk_param.

>>   #else
>>   static inline int xsk_generic_rcv(struct xdp_sock *xs, struct 
>> xdp_buff *xdp)
>>   {
>> @@ -367,6 +373,11 @@ static inline u64 xsk_umem_adjust_offset(struct 
>> xdp_umem *umem, u64 handle,
>>       return 0;
>>   }
>> +static inline u32 xsk_umem_xdp_frame_sz(struct xdp_umem *umem)
>> +{
>> +    return 0;
>> +}
>> +
>>   static inline int __xsk_map_redirect(struct xdp_sock *xs, struct 
>> xdp_buff *xdp)
>>   {
>>       return -EOPNOTSUPP;
>>
>>