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 14:07:57 +00:00
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/* SPDX-License-Identifier: GPL-2.0 */
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rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
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|
#ifndef _LINUX_RCULIST_NULLS_H
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#define _LINUX_RCULIST_NULLS_H
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#ifdef __KERNEL__
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/*
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* RCU-protected list version
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|
*/
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#include <linux/list_nulls.h>
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#include <linux/rcupdate.h>
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/**
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* hlist_nulls_del_init_rcu - deletes entry from hash list with re-initialization
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* @n: the element to delete from the hash list.
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*
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* Note: hlist_nulls_unhashed() on the node return true after this. It is
|
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* useful for RCU based read lockfree traversal if the writer side
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* must know if the list entry is still hashed or already unhashed.
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*
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* In particular, it means that we can not poison the forward pointers
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* that may still be used for walking the hash list and we can only
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* zero the pprev pointer so list_unhashed() will return true after
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* this.
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*
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* The caller must take whatever precautions are necessary (such as
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* holding appropriate locks) to avoid racing with another
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* list-mutation primitive, such as hlist_nulls_add_head_rcu() or
|
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* hlist_nulls_del_rcu(), running on this same list. However, it is
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* perfectly legal to run concurrently with the _rcu list-traversal
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* primitives, such as hlist_nulls_for_each_entry_rcu().
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*/
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static inline void hlist_nulls_del_init_rcu(struct hlist_nulls_node *n)
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{
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if (!hlist_nulls_unhashed(n)) {
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__hlist_nulls_del(n);
|
2019-11-09 17:42:13 +00:00
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|
WRITE_ONCE(n->pprev, NULL);
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
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}
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}
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2019-12-05 06:16:49 +00:00
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/**
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* hlist_nulls_first_rcu - returns the first element of the hash list.
|
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* @head: the head of the list.
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*/
|
2010-02-25 15:55:13 +00:00
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#define hlist_nulls_first_rcu(head) \
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(*((struct hlist_nulls_node __rcu __force **)&(head)->first))
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2019-12-05 06:16:49 +00:00
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/**
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* hlist_nulls_next_rcu - returns the element of the list after @node.
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* @node: element of the list.
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*/
|
2010-02-25 15:55:13 +00:00
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#define hlist_nulls_next_rcu(node) \
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(*((struct hlist_nulls_node __rcu __force **)&(node)->next))
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|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
/**
|
|
|
|
* hlist_nulls_del_rcu - deletes entry from hash list without re-initialization
|
|
|
|
* @n: the element to delete from the hash list.
|
|
|
|
*
|
|
|
|
* Note: hlist_nulls_unhashed() on entry does not return true after this,
|
|
|
|
* the entry is in an undefined state. It is useful for RCU based
|
|
|
|
* lockfree traversal.
|
|
|
|
*
|
|
|
|
* In particular, it means that we can not poison the forward
|
|
|
|
* pointers that may still be used for walking the hash list.
|
|
|
|
*
|
|
|
|
* The caller must take whatever precautions are necessary
|
|
|
|
* (such as holding appropriate locks) to avoid racing
|
|
|
|
* with another list-mutation primitive, such as hlist_nulls_add_head_rcu()
|
|
|
|
* or hlist_nulls_del_rcu(), running on this same list.
|
|
|
|
* However, it is perfectly legal to run concurrently with
|
|
|
|
* the _rcu list-traversal primitives, such as
|
|
|
|
* hlist_nulls_for_each_entry().
|
|
|
|
*/
|
|
|
|
static inline void hlist_nulls_del_rcu(struct hlist_nulls_node *n)
|
|
|
|
{
|
|
|
|
__hlist_nulls_del(n);
|
2019-11-09 17:42:13 +00:00
|
|
|
WRITE_ONCE(n->pprev, LIST_POISON2);
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* hlist_nulls_add_head_rcu
|
|
|
|
* @n: the element to add to the hash list.
|
|
|
|
* @h: the list to add to.
|
|
|
|
*
|
|
|
|
* Description:
|
|
|
|
* Adds the specified element to the specified hlist_nulls,
|
|
|
|
* while permitting racing traversals.
|
|
|
|
*
|
|
|
|
* The caller must take whatever precautions are necessary
|
|
|
|
* (such as holding appropriate locks) to avoid racing
|
|
|
|
* with another list-mutation primitive, such as hlist_nulls_add_head_rcu()
|
|
|
|
* or hlist_nulls_del_rcu(), running on this same list.
|
|
|
|
* However, it is perfectly legal to run concurrently with
|
|
|
|
* the _rcu list-traversal primitives, such as
|
|
|
|
* hlist_nulls_for_each_entry_rcu(), used to prevent memory-consistency
|
|
|
|
* problems on Alpha CPUs. Regardless of the type of CPU, the
|
|
|
|
* list-traversal primitive must be guarded by rcu_read_lock().
|
|
|
|
*/
|
|
|
|
static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
|
|
|
|
struct hlist_nulls_head *h)
|
|
|
|
{
|
|
|
|
struct hlist_nulls_node *first = h->first;
|
|
|
|
|
|
|
|
n->next = first;
|
2019-11-09 17:42:13 +00:00
|
|
|
WRITE_ONCE(n->pprev, &h->first);
|
2010-02-25 15:55:13 +00:00
|
|
|
rcu_assign_pointer(hlist_nulls_first_rcu(h), n);
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
if (!is_a_nulls(first))
|
2019-11-09 17:42:13 +00:00
|
|
|
WRITE_ONCE(first->pprev, &n->next);
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
}
|
2016-04-12 17:11:25 +00:00
|
|
|
|
2019-12-14 02:20:41 +00:00
|
|
|
/**
|
|
|
|
* hlist_nulls_add_tail_rcu
|
|
|
|
* @n: the element to add to the hash list.
|
|
|
|
* @h: the list to add to.
|
|
|
|
*
|
|
|
|
* Description:
|
|
|
|
* Adds the specified element to the specified hlist_nulls,
|
|
|
|
* while permitting racing traversals.
|
|
|
|
*
|
|
|
|
* The caller must take whatever precautions are necessary
|
|
|
|
* (such as holding appropriate locks) to avoid racing
|
|
|
|
* with another list-mutation primitive, such as hlist_nulls_add_head_rcu()
|
|
|
|
* or hlist_nulls_del_rcu(), running on this same list.
|
|
|
|
* However, it is perfectly legal to run concurrently with
|
|
|
|
* the _rcu list-traversal primitives, such as
|
|
|
|
* hlist_nulls_for_each_entry_rcu(), used to prevent memory-consistency
|
|
|
|
* problems on Alpha CPUs. Regardless of the type of CPU, the
|
|
|
|
* list-traversal primitive must be guarded by rcu_read_lock().
|
|
|
|
*/
|
|
|
|
static inline void hlist_nulls_add_tail_rcu(struct hlist_nulls_node *n,
|
|
|
|
struct hlist_nulls_head *h)
|
|
|
|
{
|
|
|
|
struct hlist_nulls_node *i, *last = NULL;
|
|
|
|
|
|
|
|
/* Note: write side code, so rcu accessors are not needed. */
|
|
|
|
for (i = h->first; !is_a_nulls(i); i = i->next)
|
|
|
|
last = i;
|
|
|
|
|
|
|
|
if (last) {
|
|
|
|
n->next = last->next;
|
|
|
|
n->pprev = &last->next;
|
|
|
|
rcu_assign_pointer(hlist_next_rcu(last), n);
|
|
|
|
} else {
|
|
|
|
hlist_nulls_add_head_rcu(n, h);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
netfilter: conntrack: allow insertion of clashing entries
This patch further relaxes the need to drop an skb due to a clash with
an existing conntrack entry.
Current clash resolution handles the case where the clash occurs between
two identical entries (distinct nf_conn objects with same tuples), i.e.:
Original Reply
existing: 10.2.3.4:42 -> 10.8.8.8:53 10.2.3.4:42 <- 10.0.0.6:5353
clashing: 10.2.3.4:42 -> 10.8.8.8:53 10.2.3.4:42 <- 10.0.0.6:5353
... existing handling will discard the unconfirmed clashing entry and
makes skb->_nfct point to the existing one. The skb can then be
processed normally just as if the clash would not have existed in the
first place.
For other clashes, the skb needs to be dropped.
This frequently happens with DNS resolvers that send A and AAAA queries
back-to-back when NAT rules are present that cause packets to get
different DNAT transformations applied, for example:
-m statistics --mode random ... -j DNAT --dnat-to 10.0.0.6:5353
-m statistics --mode random ... -j DNAT --dnat-to 10.0.0.7:5353
In this case the A or AAAA query is dropped which incurs a costly
delay during name resolution.
This patch also allows this collision type:
Original Reply
existing: 10.2.3.4:42 -> 10.8.8.8:53 10.2.3.4:42 <- 10.0.0.6:5353
clashing: 10.2.3.4:42 -> 10.8.8.8:53 10.2.3.4:42 <- 10.0.0.7:5353
In this case, clash is in original direction -- the reply direction
is still unique.
The change makes it so that when the 2nd colliding packet is received,
the clashing conntrack is tagged with new IPS_NAT_CLASH_BIT, gets a fixed
1 second timeout and is inserted in the reply direction only.
The entry is hidden from 'conntrack -L', it will time out quickly
and it can be early dropped because it will never progress to the
ASSURED state.
To avoid special-casing the delete code path to special case
the ORIGINAL hlist_nulls node, a new helper, "hlist_nulls_add_fake", is
added so hlist_nulls_del() will work.
Example:
CPU A: CPU B:
1. 10.2.3.4:42 -> 10.8.8.8:53 (A)
2. 10.2.3.4:42 -> 10.8.8.8:53 (AAAA)
3. Apply DNAT, reply changed to 10.0.0.6
4. 10.2.3.4:42 -> 10.8.8.8:53 (AAAA)
5. Apply DNAT, reply changed to 10.0.0.7
6. confirm/commit to conntrack table, no collisions
7. commit clashing entry
Reply comes in:
10.2.3.4:42 <- 10.0.0.6:5353 (A)
-> Finds a conntrack, DNAT is reversed & packet forwarded to 10.2.3.4:42
10.2.3.4:42 <- 10.0.0.7:5353 (AAAA)
-> Finds a conntrack, DNAT is reversed & packet forwarded to 10.2.3.4:42
The conntrack entry is deleted from table, as it has the NAT_CLASH
bit set.
In case of a retransmit from ORIGINAL dir, all further packets will get
the DNAT transformation to 10.0.0.6.
I tried to come up with other solutions but they all have worse
problems.
Alternatives considered were:
1. Confirm ct entries at allocation time, not in postrouting.
a. will cause uneccesarry work when the skb that creates the
conntrack is dropped by ruleset.
b. in case nat is applied, ct entry would need to be moved in
the table, which requires another spinlock pair to be taken.
c. breaks the 'unconfirmed entry is private to cpu' assumption:
we would need to guard all nfct->ext allocation requests with
ct->lock spinlock.
2. Make the unconfirmed list a hash table instead of a pcpu list.
Shares drawback c) of the first alternative.
3. Document this is expected and force users to rearrange their
ruleset (e.g. by using "-m cluster" instead of "-m statistics").
nft has the 'jhash' expression which can be used instead of 'numgen'.
Major drawback: doesn't fix what I consider a bug, not very realistic
and I believe its reasonable to have the existing rulesets to 'just
work'.
4. Document this is expected and force users to steer problematic
packets to the same CPU -- this would serialize the "allocate new
conntrack entry/nat table evaluation/perform nat/confirm entry", so
no race can occur. Similar drawback to 3.
Another advantage of this patch compared to 1) and 2) is that there are
no changes to the hot path; things are handled in the udp tracker and
the clash resolution path.
Cc: rcu@vger.kernel.org
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2020-02-03 16:37:07 +00:00
|
|
|
/* after that hlist_nulls_del will work */
|
|
|
|
static inline void hlist_nulls_add_fake(struct hlist_nulls_node *n)
|
|
|
|
{
|
|
|
|
n->pprev = &n->next;
|
|
|
|
n->next = (struct hlist_nulls_node *)NULLS_MARKER(NULL);
|
|
|
|
}
|
|
|
|
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
/**
|
|
|
|
* hlist_nulls_for_each_entry_rcu - iterate over rcu list of given type
|
|
|
|
* @tpos: the type * to use as a loop cursor.
|
|
|
|
* @pos: the &struct hlist_nulls_node to use as a loop cursor.
|
2019-12-05 18:53:52 +00:00
|
|
|
* @head: the head of the list.
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
* @member: the name of the hlist_nulls_node within the struct.
|
|
|
|
*
|
2013-05-29 09:06:27 +00:00
|
|
|
* The barrier() is needed to make sure compiler doesn't cache first element [1],
|
|
|
|
* as this loop can be restarted [2]
|
2021-01-15 15:11:45 +00:00
|
|
|
* [1] Documentation/memory-barriers.txt around line 1533
|
2020-04-21 17:04:05 +00:00
|
|
|
* [2] Documentation/RCU/rculist_nulls.rst around line 146
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
*/
|
2010-02-25 15:55:13 +00:00
|
|
|
#define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member) \
|
2013-05-29 09:06:27 +00:00
|
|
|
for (({barrier();}), \
|
|
|
|
pos = rcu_dereference_raw(hlist_nulls_first_rcu(head)); \
|
2010-02-25 15:55:13 +00:00
|
|
|
(!is_a_nulls(pos)) && \
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1; }); \
|
2010-02-25 15:55:13 +00:00
|
|
|
pos = rcu_dereference_raw(hlist_nulls_next_rcu(pos)))
|
rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
|
|
|
|
2017-03-08 04:00:13 +00:00
|
|
|
/**
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* hlist_nulls_for_each_entry_safe -
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* iterate over list of given type safe against removal of list entry
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* @tpos: the type * to use as a loop cursor.
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* @pos: the &struct hlist_nulls_node to use as a loop cursor.
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2019-12-05 18:53:52 +00:00
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* @head: the head of the list.
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2017-03-08 04:00:13 +00:00
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* @member: the name of the hlist_nulls_node within the struct.
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*/
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#define hlist_nulls_for_each_entry_safe(tpos, pos, head, member) \
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for (({barrier();}), \
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pos = rcu_dereference_raw(hlist_nulls_first_rcu(head)); \
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(!is_a_nulls(pos)) && \
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({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); \
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pos = rcu_dereference_raw(hlist_nulls_next_rcu(pos)); 1; });)
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rcu: Introduce hlist_nulls variant of hlist
hlist uses NULL value to finish a chain.
hlist_nulls variant use the low order bit set to 1 to signal an end-of-list marker.
This allows to store many different end markers, so that some RCU lockless
algos (used in TCP/UDP stack for example) can save some memory barriers in
fast paths.
Two new files are added :
include/linux/list_nulls.h
- mimics hlist part of include/linux/list.h, derived to hlist_nulls variant
include/linux/rculist_nulls.h
- mimics hlist part of include/linux/rculist.h, derived to hlist_nulls variant
Only four helpers are declared for the moment :
hlist_nulls_del_init_rcu(), hlist_nulls_del_rcu(),
hlist_nulls_add_head_rcu() and hlist_nulls_for_each_entry_rcu()
prefetches() were removed, since an end of list is not anymore NULL value.
prefetches() could trigger useless (and possibly dangerous) memory transactions.
Example of use (extracted from __udp4_lib_lookup())
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
int score, badness;
rcu_read_lock();
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != hash)
goto begin;
if (result) {
if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {
sock_put(result);
goto begin;
}
}
rcu_read_unlock();
return result;
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-17 03:37:55 +00:00
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#endif
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#endif
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