net/mlx4_en: Add accelerated RFS support
Use RFS infrastructure and flow steering in HW to keep CPU affinity of rx interrupts and application per TCP stream. A flow steering filter is added to the HW whenever the RFS ndo callback is invoked by core networking code. Because the invocation takes place in interrupt context, the actual setup of HW is done using workqueue. Whenever new filter is added, the driver checks for expiry of existing filters. Since there's window in time between the point where the core RFS code invoked the ndo callback, to the point where the HW is configured from the workqueue context, the 2nd, 3rd etc packets from that stream will cause the net core to invoke the callback again and again. To prevent inefficient/double configuration of the HW, the filters are kept in a database which is indexed using hash function to enable fast access. Signed-off-by:Amir Vadai <amirv@mellanox.com> Signed-off-by: