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authorLinus Torvalds <torvalds@linux-foundation.org>2024-07-25 13:32:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-07-25 13:32:25 -0700
commit1722389b0d863056d78287a120a1d6cadb8d4f7b (patch)
tree95c3c3b1ca6213eecbfc584b58b7676673e3696e /Documentation
parent8bf100092d60bf586bbc1a3a2cd833bb212d9d53 (diff)
parentaf65ea42bd1d28d818b74b9b3b4f8da7ada9f88b (diff)
Merge tag 'net-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski: "Including fixes from bpf and netfilter. A lot of networking people were at a conference last week, busy catching COVID, so relatively short PR. Current release - regressions: - tcp: process the 3rd ACK with sk_socket for TFO and MPTCP Current release - new code bugs: - l2tp: protect session IDR and tunnel session list with one lock, make sure the state is coherent to avoid a warning - eth: bnxt_en: update xdp_rxq_info in queue restart logic - eth: airoha: fix location of the MBI_RX_AGE_SEL_MASK field Previous releases - regressions: - xsk: require XDP_UMEM_TX_METADATA_LEN to actuate tx_metadata_len, the field reuses previously un-validated pad Previous releases - always broken: - tap/tun: drop short frames to prevent crashes later in the stack - eth: ice: add a per-VF limit on number of FDIR filters - af_unix: disable MSG_OOB handling for sockets in sockmap/sockhash" * tag 'net-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (34 commits) tun: add missing verification for short frame tap: add missing verification for short frame mISDN: Fix a use after free in hfcmulti_tx() gve: Fix an edge case for TSO skb validity check bnxt_en: update xdp_rxq_info in queue restart logic tcp: process the 3rd ACK with sk_socket for TFO/MPTCP selftests/bpf: Add XDP_UMEM_TX_METADATA_LEN to XSK TX metadata test xsk: Require XDP_UMEM_TX_METADATA_LEN to actuate tx_metadata_len bpf: Fix a segment issue when downgrading gso_size net: mediatek: Fix potential NULL pointer dereference in dummy net_device handling MAINTAINERS: make Breno the netconsole maintainer MAINTAINERS: Update bonding entry net: nexthop: Initialize all fields in dumped nexthops net: stmmac: Correct byte order of perfect_match selftests: forwarding: skip if kernel not support setting bridge fdb learning limit tipc: Return non-zero value from tipc_udp_addr2str() on error netfilter: nft_set_pipapo_avx2: disable softinterrupts ice: Fix recipe read procedure ice: Add a per-VF limit on number of FDIR filters net: bonding: correctly annotate RCU in bond_should_notify_peers() ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/networking/xsk-tx-metadata.rst16
1 files changed, 10 insertions, 6 deletions
diff --git a/Documentation/networking/xsk-tx-metadata.rst b/Documentation/networking/xsk-tx-metadata.rst
index bd033fe95cca..e76b0cfc32f7 100644
--- a/Documentation/networking/xsk-tx-metadata.rst
+++ b/Documentation/networking/xsk-tx-metadata.rst
@@ -11,12 +11,16 @@ metadata on the receive side.
General Design
==============
-The headroom for the metadata is reserved via ``tx_metadata_len`` in
-``struct xdp_umem_reg``. The metadata length is therefore the same for
-every socket that shares the same umem. The metadata layout is a fixed UAPI,
-refer to ``union xsk_tx_metadata`` in ``include/uapi/linux/if_xdp.h``.
-Thus, generally, the ``tx_metadata_len`` field above should contain
-``sizeof(union xsk_tx_metadata)``.
+The headroom for the metadata is reserved via ``tx_metadata_len`` and
+``XDP_UMEM_TX_METADATA_LEN`` flag in ``struct xdp_umem_reg``. The metadata
+length is therefore the same for every socket that shares the same umem.
+The metadata layout is a fixed UAPI, refer to ``union xsk_tx_metadata`` in
+``include/uapi/linux/if_xdp.h``. Thus, generally, the ``tx_metadata_len``
+field above should contain ``sizeof(union xsk_tx_metadata)``.
+
+Note that in the original implementation the ``XDP_UMEM_TX_METADATA_LEN``
+flag was not required. Applications might attempt to create a umem
+with a flag first and if it fails, do another attempt without a flag.
The headroom and the metadata itself should be located right before
``xdp_desc->addr`` in the umem frame. Within a frame, the metadata