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Subject[PATCH v3 net-next 0/9] net: intel: napi_alloc_skb() vs metadata
Date
This is an interpolation of [0] to other Intel Ethernet drivers
(and is (re)based on its code).
The main aim is to keep XDP metadata not only in case with
build_skb(), but also when we do napi_alloc_skb() + memcpy().

All Intel drivers suffers from the same here:
- metadata gets lost on XDP_PASS in legacy-rx;
- excessive headroom allocation on XSK Rx to skbs;
- metadata gets lost on XSK Rx to skbs.

Those get especially actual in XDP Hints upcoming.
I couldn't have addressed the first one for all Intel drivers due to
that they don't reserve any headroom for now in legacy-rx mode even
with XDP enabled. This is hugely wrong, but requires quite a bunch
of work and a separate series. Luckily, ice doesn't suffer from
that.
igc has 1 and 3 already fixed in [0].

From v2 (unreleased upstream):
- tweaked 007 to pass bi->xdp directly and simplify code (Maciej);
- picked Michal's Reviewed-by.

From v1 (unreleased upstream):
- drop "fixes" of legacy-rx for i40e, igb and ixgbe since they have
another flaw regarding headroom (see above);
- drop igc cosmetic fixes since they landed upstream incorporated
into Jesper's commits;
- picked one Acked-by from Maciej.

[0] https://lore.kernel.org/netdev/163700856423.565980.10162564921347693758.stgit@firesoul

Alexander Lobakin (9):
i40e: don't reserve excessive XDP_PACKET_HEADROOM on XSK Rx to skb
i40e: respect metadata on XSK Rx to skb
ice: respect metadata in legacy-rx/ice_construct_skb()
ice: don't reserve excessive XDP_PACKET_HEADROOM on XSK Rx to skb
ice: respect metadata on XSK Rx to skb
igc: don't reserve excessive XDP_PACKET_HEADROOM on XSK Rx to skb
ixgbe: pass bi->xdp to ixgbe_construct_skb_zc() directly
ixgbe: don't reserve excessive XDP_PACKET_HEADROOM on XSK Rx to skb
i40e: respect metadata on XSK Rx to skb

drivers/net/ethernet/intel/i40e/i40e_xsk.c | 16 +++++++-----
drivers/net/ethernet/intel/ice/ice_txrx.c | 15 ++++++++---
drivers/net/ethernet/intel/ice/ice_xsk.c | 16 +++++++-----
drivers/net/ethernet/intel/igc/igc_main.c | 13 +++++-----
drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 27 ++++++++++++--------
5 files changed, 54 insertions(+), 33 deletions(-)

--
Testing hints:

Setup an XDP and AF_XDP program which will prepend metadata at the
front of the frames and return XDP_PASS, then check that metadata
is present after frames reach kernel network stack.
--
2.33.1

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