• David Howells's avatar
    rxrpc: Use IDR to allocate client conn IDs on a machine-wide basis · 4a3388c8
    David Howells authored
    Use the IDR facility to allocate client connection IDs on a machine-wide
    basis so that each client connection has a unique identifier.  When the
    connection ID space wraps, we advance the epoch by 1, thereby effectively
    having a 62-bit ID space.  The IDR facility is then used to look up client
    connections during incoming packet routing instead of using an rbtree
    rooted on the transport.
    
    This change allows for the removal of the transport in the future and also
    means that client connections can be looked up directly in the data-ready
    handler by connection ID.
    
    The ID management code is placed in a new file, conn-client.c, to which all
    the client connection-specific code will eventually move.
    
    Note that the IDR tree gets very expensive on memory if the connection IDs
    are widely scattered throughout the number space, so we shall need to
    retire connections that have, say, an ID more than four times the maximum
    number of client conns away from the current allocation point to try and
    keep the IDs concentrated.  We will also need to retire connections from an
    old epoch.
    
    Also note that, for the moment, a pointer to the transport has to be passed
    through into the ID allocation function so that we can take a BH lock to
    prevent a locking issue against in-BH lookup of client connections.  This
    will go away later when RCU is used for server connections also.
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    4a3388c8
Makefile 506 Bytes