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    bpf: offload: add map offload infrastructure · a3884572
    Jakub Kicinski 提交于
    BPF map offload follow similar path to program offload.  At creation
    time users may specify ifindex of the device on which they want to
    create the map.  Map will be validated by the kernel's
    .map_alloc_check callback and device driver will be called for the
    actual allocation.  Map will have an empty set of operations
    associated with it (save for alloc and free callbacks).  The real
    device callbacks are kept in map->offload->dev_ops because they
    have slightly different signatures.  Map operations are called in
    process context so the driver may communicate with HW freely,
    msleep(), wait() etc.
    
    Map alloc and free callbacks are muxed via existing .ndo_bpf, and
    are always called with rtnl lock held.  Maps and programs are
    guaranteed to be destroyed before .ndo_uninit (i.e. before
    unregister_netdev() returns).  Map callbacks are invoked with
    bpf_devs_lock *read* locked, drivers must take care of exclusive
    locking if necessary.
    
    All offload-specific branches are marked with unlikely() (through
    bpf_map_is_dev_bound()), given that branch penalty will be
    negligible compared to IO anyway, and we don't want to penalize
    SW path unnecessarily.
    Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
    Reviewed-by: NQuentin Monnet <quentin.monnet@netronome.com>
    Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
    a3884572
bpf.h 30.8 KB