• David Decotigny's avatar
    net: ethtool: add new ETHTOOL_xLINKSETTINGS API · 3f1ac7a7
    David Decotigny authored
    This patch defines a new ETHTOOL_GLINKSETTINGS/SLINKSETTINGS API,
    handled by the new get_link_ksettings/set_link_ksettings callbacks.
    This API provides support for most legacy ethtool_cmd fields, adds
    support for larger link mode masks (up to 4064 bits, variable length),
    and removes ethtool_cmd deprecated
    fields (transceiver/maxrxpkt/maxtxpkt).
    
    This API is deprecating the legacy ETHTOOL_GSET/SSET API and provides
    the following backward compatibility properties:
     - legacy ethtool with legacy drivers: no change, still using the
       get_settings/set_settings callbacks.
     - legacy ethtool with new get/set_link_ksettings drivers: the new
       driver callbacks are used, data internally converted to legacy
       ethtool_cmd. ETHTOOL_GSET will return only the 1st 32b of each link
       mode mask. ETHTOOL_SSET will fail if user tries to set the
       ethtool_cmd deprecated fields to
       non-0 (transceiver/maxrxpkt/maxtxpkt). A kernel warning is logged if
       driver sets higher bits.
     - future ethtool with legacy drivers: no change, still using the
       get_settings/set_settings callbacks, internally converted to new data
       structure. Deprecated fields (transceiver/maxrxpkt/maxtxpkt) will be
       ignored and seen as 0 from user space. Note that that "future"
       ethtool tool will not allow changes to these deprecated fields.
     - future ethtool with new drivers: direct call to the new callbacks.
    
    By "future" ethtool, what is meant is:
     - query: first try ETHTOOL_GLINKSETTINGS, and revert to ETHTOOL_GSET if
       fails
     - set: query first and remember which of ETHTOOL_GLINKSETTINGS or
       ETHTOOL_GSET was successful
       + if ETHTOOL_GLINKSETTINGS was successful, then change config with
         ETHTOOL_SLINKSETTINGS. A failure there is final (do not try
         ETHTOOL_SSET).
       + otherwise ETHTOOL_GSET was successful, change config with
         ETHTOOL_SSET. A failure there is final (do not try
         ETHTOOL_SLINKSETTINGS).
    
    The interaction user/kernel via the new API requires a small
    ETHTOOL_GLINKSETTINGS handshake first to agree on the length of the link
    mode bitmaps. If kernel doesn't agree with user, it returns the bitmap
    length it is expecting from user as a negative length (and cmd field is
    0). When kernel and user agree, kernel returns valid info in all
    fields (ie. link mode length > 0 and cmd is ETHTOOL_GLINKSETTINGS).
    
    Data structure crossing user/kernel boundary is 32/64-bit
    agnostic. Converted internally to a legal kernel bitmap.
    
    The internal __ethtool_get_settings kernel helper will gradually be
    replaced by __ethtool_get_link_ksettings by the time the first
    "link_settings" drivers start to appear. So this patch doesn't change
    it, it will be removed before it needs to be changed.
    Signed-off-by: default avatarDavid Decotigny <decot@googlers.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    3f1ac7a7
ethtool.c 68.4 KB