[bpf-next,2/3] ixgbe: fix xdp handle calculations

Commit 7cbbf9f1fa23 ("ixgbe: fix xdp handle calculations") reintroduced
the addition of the umem headroom to the xdp handle in the ixgbe_zca_free,
ixgbe_alloc_buffer_slow_zc and ixgbe_alloc_buffer_zc functions. However,
the headroom is already added to the handle in the function
ixgbe_run_xdp_zc. This commit removes the latter addition and fixes the
case where the headroom is non-zero.

Fixes: 7cbbf9f1fa23 ("ixgbe: fix xdp handle calculations")
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On
> Behalf Of Ciara Loftus
> Sent: Wednesday, September 11, 2019 10:25 AM
> To: netdev@vger.kernel.org; ast@kernel.org; daniel@iogearbox.net; Topel,
> Bjorn <bjorn.topel@intel.com>; Karlsson, Magnus
> <magnus.karlsson@intel.com>; jonathan.lemon@gmail.com
> Cc: Richardson, Bruce <bruce.richardson@intel.com>; bpf@vger.kernel.org;
> intel-wired-lan@lists.osuosl.org; Loftus, Ciara <ciara.loftus@intel.com>;
> Laatz, Kevin <kevin.laatz@intel.com>
> Subject: [Intel-wired-lan] [PATCH bpf-next 2/3] ixgbe: fix xdp handle
> calculations
> 
> Commit 7cbbf9f1fa23 ("ixgbe: fix xdp handle calculations") reintroduced the
> addition of the umem headroom to the xdp handle in the ixgbe_zca_free,
> ixgbe_alloc_buffer_slow_zc and ixgbe_alloc_buffer_zc functions. However,
> the headroom is already added to the handle in the function
> ixgbe_run_xdp_zc. This commit removes the latter addition and fixes the
> case where the headroom is non-zero.
> 
> Fixes: 7cbbf9f1fa23 ("ixgbe: fix xdp handle calculations")
> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>

On Wed, 11 Sep 2019 at 19:27, Ciara Loftus <ciara.loftus@intel.com> wrote:
>
> Commit 7cbbf9f1fa23 ("ixgbe: fix xdp handle calculations") reintroduced
> the addition of the umem headroom to the xdp handle in the ixgbe_zca_free,
> ixgbe_alloc_buffer_slow_zc and ixgbe_alloc_buffer_zc functions. However,
> the headroom is already added to the handle in the function
> ixgbe_run_xdp_zc. This commit removes the latter addition and fixes the
> case where the headroom is non-zero.
>
> Fixes: 7cbbf9f1fa23 ("ixgbe: fix xdp handle calculations")
> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> index ad802a8909e0..5ed8b5a257cf 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> @@ -145,7 +145,7 @@ static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter,
>  {
>         struct xdp_umem *umem = rx_ring->xsk_umem;
>         int err, result = IXGBE_XDP_PASS;
> -       u64 offset = umem->headroom;
> +       u64 offset;

...and same comment as from the i40e patch: Reverse xmas tree, please.


Cheers,
Björn

>         struct bpf_prog *xdp_prog;
>         struct xdp_frame *xdpf;
>         u32 act;
> @@ -153,7 +153,7 @@ static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter,
>         rcu_read_lock();
>         xdp_prog = READ_ONCE(rx_ring->xdp_prog);
>         act = bpf_prog_run_xdp(xdp_prog, xdp);
> -       offset += xdp->data - xdp->data_hard_start;
> +       offset = xdp->data - xdp->data_hard_start;
>
>         xdp->handle = xsk_umem_adjust_offset(umem, xdp->handle, offset);
>
> --
> 2.17.1
>