treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[DCCP] ccid3: Finer-grained resolution of sending rates

This patch
* resolves a bug where packets smaller than 32/64 bytes resulted in sending rates of 0
* supports all sending rates from 1/64 bytes/second up to 4Gbyte/second
* simplifies the present overflow problems in calculations

Current sending rate X and the cached value X_recv of the receiver-estimated
sending rate are both scaled by 64 (2^6) in order to
* cope with low sending rates (minimally 1 byte/second)
* allow upgrading to use a packets-per-second implementation of CCID 3
* avoid calculation errors due to integer arithmetic cut-off

The patch implements a revised strategy from
http://www.mail-archive.com/dccp@vger.kernel.org/msg01040.html

The only difference with regard to that strategy is that t_ipi is already
used in the calculation of the nofeedback timeout, which saves one division.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

[NET]: Add documentation for TFRC structures

This adds documentation for the TFRC structure fields.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

[CCID3]: Introduce include/linux/tfrc.h

Moving the TFRC sender and receiver variables to separate structs, so
that we can copy these structs to userspace thru getsockopt,
dccp_diag, etc.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>