License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 17:07:57 +03:00
// SPDX-License-Identifier: GPL-2.0
2015-10-17 07:57:46 +03:00
# include <linux/tcp.h>
# include <net/tcp.h>
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void tcp_mark_skb_lost ( struct sock * sk , struct sk_buff * skb )
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{
struct tcp_sock * tp = tcp_sk ( sk ) ;
tcp_skb_mark_lost_uncond_verify ( tp , skb ) ;
if ( TCP_SKB_CB ( skb ) - > sacked & TCPCB_SACKED_RETRANS ) {
/* Account for retransmits that are lost again */
TCP_SKB_CB ( skb ) - > sacked & = ~ TCPCB_SACKED_RETRANS ;
tp - > retrans_out - = tcp_skb_pcount ( skb ) ;
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NET_ADD_STATS ( sock_net ( sk ) , LINUX_MIB_TCPLOSTRETRANSMIT ,
tcp_skb_pcount ( skb ) ) ;
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}
}
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static bool tcp_rack_sent_after ( u64 t1 , u64 t2 , u32 seq1 , u32 seq2 )
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{
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return t1 > t2 | | ( t1 = = t2 & & after ( seq1 , seq2 ) ) ;
2017-01-13 09:11:34 +03:00
}
tcp: support DUPACK threshold in RACK
This patch adds support for the classic DUPACK threshold rule
(#DupThresh) in RACK.
When the number of packets SACKed is greater or equal to the
threshold, RACK sets the reordering window to zero which would
immediately mark all the unsacked packets below the highest SACKed
sequence lost. Since this approach is known to not work well with
reordering, RACK only uses it if no reordering has been observed.
The DUPACK threshold rule is a particularly useful extension to the
fast recoveries triggered by RACK reordering timer. For example
data-center transfers where the RTT is much smaller than a timer
tick, or high RTT path where the default RTT/4 may take too long.
Note that this patch differs slightly from RFC6675. RFC6675
considers a packet lost when at least #DupThresh higher-sequence
packets are SACKed.
With RACK, for connections that have seen reordering, RACK
continues to use a dynamically-adaptive time-based reordering
window to detect losses. But for connections on which we have not
yet seen reordering, this patch considers a packet lost when at
least one higher sequence packet is SACKed and the total number
of SACKed packets is at least DupThresh. For example, suppose a
connection has not seen reordering, and sends 10 packets, and
packets 3, 5, 7 are SACKed. RFC6675 considers packets 1 and 2
lost. RACK considers packets 1, 2, 4, 6 lost.
There is some small risk of spurious retransmits here due to
reordering. However, this is mostly limited to the first flight of
a connection on which the sender receives SACKs from reordering.
And RFC 6675 and FACK loss detection have a similar risk on the
first flight with reordering (it's just that the risk of spurious
retransmits from reordering was slightly narrower for those older
algorithms due to the margin of 3*MSS).
Also the minimum reordering window is reduced from 1 msec to 0
to recover quicker on short RTT transfers. Therefore RACK is more
aggressive in marking packets lost during recovery to reduce the
reordering window timeouts.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-17 02:40:10 +03:00
u32 tcp_rack_reo_wnd ( const struct sock * sk )
{
struct tcp_sock * tp = tcp_sk ( sk ) ;
if ( ! tp - > rack . reord ) {
/* If reordering has not been observed, be aggressive during
* the recovery or starting the recovery by DUPACK threshold .
*/
if ( inet_csk ( sk ) - > icsk_ca_state > = TCP_CA_Recovery )
return 0 ;
if ( tp - > sacked_out > = tp - > reordering & &
! ( sock_net ( sk ) - > ipv4 . sysctl_tcp_recovery & TCP_RACK_NO_DUPTHRESH ) )
return 0 ;
}
/* To be more reordering resilient, allow min_rtt/4 settling delay.
* Use min_rtt instead of the smoothed RTT because reordering is
* often a path property and less related to queuing or delayed ACKs .
* Upon receiving DSACKs , linearly increase the window up to the
* smoothed RTT .
*/
return min ( ( tcp_min_rtt ( tp ) > > 2 ) * tp - > rack . reo_wnd_steps ,
tp - > srtt_us > > 3 ) ;
}
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s32 tcp_rack_skb_timeout ( struct tcp_sock * tp , struct sk_buff * skb , u32 reo_wnd )
{
return tp - > rack . rtt_us + reo_wnd -
tcp_stamp_us_delta ( tp - > tcp_mstamp , skb - > skb_mstamp ) ;
}
2017-01-13 09:11:36 +03:00
/* RACK loss detection (IETF draft draft-ietf-tcpm-rack-01):
*
* Marks a packet lost , if some packet sent later has been ( s ) acked .
2015-10-17 07:57:47 +03:00
* The underlying idea is similar to the traditional dupthresh and FACK
* but they look at different metrics :
*
* dupthresh : 3 OOO packets delivered ( packet count )
* FACK : sequence delta to highest sacked sequence ( sequence space )
* RACK : sent time delta to the latest delivered packet ( time domain )
*
* The advantage of RACK is it applies to both original and retransmitted
* packet and therefore is robust against tail losses . Another advantage
* is being more resilient to reordering by simply allowing some
* " settling delay " , instead of tweaking the dupthresh .
*
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* When tcp_rack_detect_loss ( ) detects some packets are lost and we
* are not already in the CA_Recovery state , either tcp_rack_reo_timeout ( )
* or tcp_time_to_recover ( ) ' s " Trick#1: the loss is proven " code path will
* make us enter the CA_Recovery state .
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*/
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static void tcp_rack_detect_loss ( struct sock * sk , u32 * reo_timeout )
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{
struct tcp_sock * tp = tcp_sk ( sk ) ;
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struct sk_buff * skb , * n ;
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u32 reo_wnd ;
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* reo_timeout = 0 ;
tcp: support DUPACK threshold in RACK
This patch adds support for the classic DUPACK threshold rule
(#DupThresh) in RACK.
When the number of packets SACKed is greater or equal to the
threshold, RACK sets the reordering window to zero which would
immediately mark all the unsacked packets below the highest SACKed
sequence lost. Since this approach is known to not work well with
reordering, RACK only uses it if no reordering has been observed.
The DUPACK threshold rule is a particularly useful extension to the
fast recoveries triggered by RACK reordering timer. For example
data-center transfers where the RTT is much smaller than a timer
tick, or high RTT path where the default RTT/4 may take too long.
Note that this patch differs slightly from RFC6675. RFC6675
considers a packet lost when at least #DupThresh higher-sequence
packets are SACKed.
With RACK, for connections that have seen reordering, RACK
continues to use a dynamically-adaptive time-based reordering
window to detect losses. But for connections on which we have not
yet seen reordering, this patch considers a packet lost when at
least one higher sequence packet is SACKed and the total number
of SACKed packets is at least DupThresh. For example, suppose a
connection has not seen reordering, and sends 10 packets, and
packets 3, 5, 7 are SACKed. RFC6675 considers packets 1 and 2
lost. RACK considers packets 1, 2, 4, 6 lost.
There is some small risk of spurious retransmits here due to
reordering. However, this is mostly limited to the first flight of
a connection on which the sender receives SACKs from reordering.
And RFC 6675 and FACK loss detection have a similar risk on the
first flight with reordering (it's just that the risk of spurious
retransmits from reordering was slightly narrower for those older
algorithms due to the margin of 3*MSS).
Also the minimum reordering window is reduced from 1 msec to 0
to recover quicker on short RTT transfers. Therefore RACK is more
aggressive in marking packets lost during recovery to reduce the
reordering window timeouts.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-17 02:40:10 +03:00
reo_wnd = tcp_rack_reo_wnd ( sk ) ;
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list_for_each_entry_safe ( skb , n , & tp - > tsorted_sent_queue ,
tcp_tsorted_anchor ) {
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struct tcp_skb_cb * scb = TCP_SKB_CB ( skb ) ;
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s32 remaining ;
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/* Skip ones marked lost but not yet retransmitted */
if ( ( scb - > sacked & TCPCB_LOST ) & &
! ( scb - > sacked & TCPCB_SACKED_RETRANS ) )
continue ;
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if ( ! tcp_rack_sent_after ( tp - > rack . mstamp , skb - > skb_mstamp ,
tp - > rack . end_seq , scb - > end_seq ) )
break ;
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/* A packet is lost if it has not been s/acked beyond
* the recent RTT plus the reordering window .
*/
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remaining = tcp_rack_skb_timeout ( tp , skb , reo_wnd ) ;
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if ( remaining < = 0 ) {
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tcp_mark_skb_lost ( sk , skb ) ;
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list_del_init ( & skb - > tcp_tsorted_anchor ) ;
} else {
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/* Record maximum wait time */
* reo_timeout = max_t ( u32 , * reo_timeout , remaining ) ;
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}
}
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}
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void tcp_rack_mark_lost ( struct sock * sk )
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{
struct tcp_sock * tp = tcp_sk ( sk ) ;
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u32 timeout ;
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if ( ! tp - > rack . advanced )
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return ;
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/* Reset the advanced flag to avoid unnecessary queue scanning */
tp - > rack . advanced = 0 ;
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tcp_rack_detect_loss ( sk , & timeout ) ;
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if ( timeout ) {
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timeout = usecs_to_jiffies ( timeout ) + TCP_TIMEOUT_MIN ;
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inet_csk_reset_xmit_timer ( sk , ICSK_TIME_REO_TIMEOUT ,
timeout , inet_csk ( sk ) - > icsk_rto ) ;
}
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}
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/* Record the most recently (re)sent time among the (s)acked packets
* This is " Step 3: Advance RACK.xmit_time and update RACK.RTT " from
* draft - cheng - tcpm - rack - 00. txt
*/
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void tcp_rack_advance ( struct tcp_sock * tp , u8 sacked , u32 end_seq ,
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u64 xmit_time )
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{
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u32 rtt_us ;
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rtt_us = tcp_stamp_us_delta ( tp - > tcp_mstamp , xmit_time ) ;
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if ( rtt_us < tcp_min_rtt ( tp ) & & ( sacked & TCPCB_RETRANS ) ) {
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/* If the sacked packet was retransmitted, it's ambiguous
* whether the retransmission or the original ( or the prior
* retransmission ) was sacked .
*
* If the original is lost , there is no ambiguity . Otherwise
* we assume the original can be delayed up to aRTT + min_rtt .
* the aRTT term is bounded by the fast recovery or timeout ,
* so it ' s at least one RTT ( i . e . , retransmission is at least
* an RTT later ) .
*/
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return ;
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}
tp - > rack . advanced = 1 ;
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tp - > rack . rtt_us = rtt_us ;
if ( tcp_rack_sent_after ( xmit_time , tp - > rack . mstamp ,
end_seq , tp - > rack . end_seq ) ) {
tp - > rack . mstamp = xmit_time ;
tp - > rack . end_seq = end_seq ;
}
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}
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/* We have waited long enough to accommodate reordering. Mark the expired
* packets lost and retransmit them .
*/
void tcp_rack_reo_timeout ( struct sock * sk )
{
struct tcp_sock * tp = tcp_sk ( sk ) ;
u32 timeout , prior_inflight ;
prior_inflight = tcp_packets_in_flight ( tp ) ;
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tcp_rack_detect_loss ( sk , & timeout ) ;
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if ( prior_inflight ! = tcp_packets_in_flight ( tp ) ) {
if ( inet_csk ( sk ) - > icsk_ca_state ! = TCP_CA_Recovery ) {
tcp_enter_recovery ( sk , false ) ;
if ( ! inet_csk ( sk ) - > icsk_ca_ops - > cong_control )
tcp_cwnd_reduction ( sk , 1 , 0 ) ;
}
tcp_xmit_retransmit_queue ( sk ) ;
}
if ( inet_csk ( sk ) - > icsk_pending ! = ICSK_TIME_RETRANS )
tcp_rearm_rto ( sk ) ;
}
2017-11-04 02:38:48 +03:00
/* Updates the RACK's reo_wnd based on DSACK and no. of recoveries.
*
* If DSACK is received , increment reo_wnd by min_rtt / 4 ( upper bounded
* by srtt ) , since there is possibility that spurious retransmission was
* due to reordering delay longer than reo_wnd .
*
* Persist the current reo_wnd value for TCP_RACK_RECOVERY_THRESH ( 16 )
* no . of successful recoveries ( accounts for full DSACK - based loss
* recovery undo ) . After that , reset it to default ( min_rtt / 4 ) .
*
* At max , reo_wnd is incremented only once per rtt . So that the new
* DSACK on which we are reacting , is due to the spurious retx ( approx )
* after the reo_wnd has been updated last time .
*
* reo_wnd is tracked in terms of steps ( of min_rtt / 4 ) , rather than
* absolute value to account for change in rtt .
*/
void tcp_rack_update_reo_wnd ( struct sock * sk , struct rate_sample * rs )
{
struct tcp_sock * tp = tcp_sk ( sk ) ;
if ( sock_net ( sk ) - > ipv4 . sysctl_tcp_recovery & TCP_RACK_STATIC_REO_WND | |
! rs - > prior_delivered )
return ;
/* Disregard DSACK if a rtt has not passed since we adjusted reo_wnd */
if ( before ( rs - > prior_delivered , tp - > rack . last_delivered ) )
tp - > rack . dsack_seen = 0 ;
/* Adjust the reo_wnd if update is pending */
if ( tp - > rack . dsack_seen ) {
tp - > rack . reo_wnd_steps = min_t ( u32 , 0xFF ,
tp - > rack . reo_wnd_steps + 1 ) ;
tp - > rack . dsack_seen = 0 ;
tp - > rack . last_delivered = tp - > delivered ;
tp - > rack . reo_wnd_persist = TCP_RACK_RECOVERY_THRESH ;
} else if ( ! tp - > rack . reo_wnd_persist ) {
tp - > rack . reo_wnd_steps = 1 ;
}
}
2018-05-17 02:40:12 +03:00
/* RFC6582 NewReno recovery for non-SACK connection. It simply retransmits
* the next unacked packet upon receiving
* a ) three or more DUPACKs to start the fast recovery
* b ) an ACK acknowledging new data during the fast recovery .
*/
void tcp_newreno_mark_lost ( struct sock * sk , bool snd_una_advanced )
{
const u8 state = inet_csk ( sk ) - > icsk_ca_state ;
struct tcp_sock * tp = tcp_sk ( sk ) ;
if ( ( state < TCP_CA_Recovery & & tp - > sacked_out > = tp - > reordering ) | |
( state = = TCP_CA_Recovery & & snd_una_advanced ) ) {
struct sk_buff * skb = tcp_rtx_queue_head ( sk ) ;
u32 mss ;
if ( TCP_SKB_CB ( skb ) - > sacked & TCPCB_LOST )
return ;
mss = tcp_skb_mss ( skb ) ;
if ( tcp_skb_pcount ( skb ) > 1 & & skb - > len > mss )
tcp_fragment ( sk , TCP_FRAG_IN_RTX_QUEUE , skb ,
mss , mss , GFP_ATOMIC ) ;
tcp_skb_mark_lost_uncond_verify ( tp , skb ) ;
}
}