linux-stable/include/linux/hashtable.h
Greg Kroah-Hartman b24413180f 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>
2017-11-02 11:10:55 +01:00

209 lines
6.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Statically sized hash table implementation
* (C) 2012 Sasha Levin <levinsasha928@gmail.com>
*/
#ifndef _LINUX_HASHTABLE_H
#define _LINUX_HASHTABLE_H
#include <linux/list.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/hash.h>
#include <linux/rculist.h>
#define DEFINE_HASHTABLE(name, bits) \
struct hlist_head name[1 << (bits)] = \
{ [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
#define DEFINE_READ_MOSTLY_HASHTABLE(name, bits) \
struct hlist_head name[1 << (bits)] __read_mostly = \
{ [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
#define DECLARE_HASHTABLE(name, bits) \
struct hlist_head name[1 << (bits)]
#define HASH_SIZE(name) (ARRAY_SIZE(name))
#define HASH_BITS(name) ilog2(HASH_SIZE(name))
/* Use hash_32 when possible to allow for fast 32bit hashing in 64bit kernels. */
#define hash_min(val, bits) \
(sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits))
static inline void __hash_init(struct hlist_head *ht, unsigned int sz)
{
unsigned int i;
for (i = 0; i < sz; i++)
INIT_HLIST_HEAD(&ht[i]);
}
/**
* hash_init - initialize a hash table
* @hashtable: hashtable to be initialized
*
* Calculates the size of the hashtable from the given parameter, otherwise
* same as hash_init_size.
*
* This has to be a macro since HASH_BITS() will not work on pointers since
* it calculates the size during preprocessing.
*/
#define hash_init(hashtable) __hash_init(hashtable, HASH_SIZE(hashtable))
/**
* hash_add - add an object to a hashtable
* @hashtable: hashtable to add to
* @node: the &struct hlist_node of the object to be added
* @key: the key of the object to be added
*/
#define hash_add(hashtable, node, key) \
hlist_add_head(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
/**
* hash_add_rcu - add an object to a rcu enabled hashtable
* @hashtable: hashtable to add to
* @node: the &struct hlist_node of the object to be added
* @key: the key of the object to be added
*/
#define hash_add_rcu(hashtable, node, key) \
hlist_add_head_rcu(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
/**
* hash_hashed - check whether an object is in any hashtable
* @node: the &struct hlist_node of the object to be checked
*/
static inline bool hash_hashed(struct hlist_node *node)
{
return !hlist_unhashed(node);
}
static inline bool __hash_empty(struct hlist_head *ht, unsigned int sz)
{
unsigned int i;
for (i = 0; i < sz; i++)
if (!hlist_empty(&ht[i]))
return false;
return true;
}
/**
* hash_empty - check whether a hashtable is empty
* @hashtable: hashtable to check
*
* This has to be a macro since HASH_BITS() will not work on pointers since
* it calculates the size during preprocessing.
*/
#define hash_empty(hashtable) __hash_empty(hashtable, HASH_SIZE(hashtable))
/**
* hash_del - remove an object from a hashtable
* @node: &struct hlist_node of the object to remove
*/
static inline void hash_del(struct hlist_node *node)
{
hlist_del_init(node);
}
/**
* hash_del_rcu - remove an object from a rcu enabled hashtable
* @node: &struct hlist_node of the object to remove
*/
static inline void hash_del_rcu(struct hlist_node *node)
{
hlist_del_init_rcu(node);
}
/**
* hash_for_each - iterate over a hashtable
* @name: hashtable to iterate
* @bkt: integer to use as bucket loop cursor
* @obj: the type * to use as a loop cursor for each entry
* @member: the name of the hlist_node within the struct
*/
#define hash_for_each(name, bkt, obj, member) \
for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
(bkt)++)\
hlist_for_each_entry(obj, &name[bkt], member)
/**
* hash_for_each_rcu - iterate over a rcu enabled hashtable
* @name: hashtable to iterate
* @bkt: integer to use as bucket loop cursor
* @obj: the type * to use as a loop cursor for each entry
* @member: the name of the hlist_node within the struct
*/
#define hash_for_each_rcu(name, bkt, obj, member) \
for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
(bkt)++)\
hlist_for_each_entry_rcu(obj, &name[bkt], member)
/**
* hash_for_each_safe - iterate over a hashtable safe against removal of
* hash entry
* @name: hashtable to iterate
* @bkt: integer to use as bucket loop cursor
* @tmp: a &struct used for temporary storage
* @obj: the type * to use as a loop cursor for each entry
* @member: the name of the hlist_node within the struct
*/
#define hash_for_each_safe(name, bkt, tmp, obj, member) \
for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
(bkt)++)\
hlist_for_each_entry_safe(obj, tmp, &name[bkt], member)
/**
* hash_for_each_possible - iterate over all possible objects hashing to the
* same bucket
* @name: hashtable to iterate
* @obj: the type * to use as a loop cursor for each entry
* @member: the name of the hlist_node within the struct
* @key: the key of the objects to iterate over
*/
#define hash_for_each_possible(name, obj, member, key) \
hlist_for_each_entry(obj, &name[hash_min(key, HASH_BITS(name))], member)
/**
* hash_for_each_possible_rcu - iterate over all possible objects hashing to the
* same bucket in an rcu enabled hashtable
* @name: hashtable to iterate
* @obj: the type * to use as a loop cursor for each entry
* @member: the name of the hlist_node within the struct
* @key: the key of the objects to iterate over
*/
#define hash_for_each_possible_rcu(name, obj, member, key) \
hlist_for_each_entry_rcu(obj, &name[hash_min(key, HASH_BITS(name))],\
member)
/**
* hash_for_each_possible_rcu_notrace - iterate over all possible objects hashing
* to the same bucket in an rcu enabled hashtable in a rcu enabled hashtable
* @name: hashtable to iterate
* @obj: the type * to use as a loop cursor for each entry
* @member: the name of the hlist_node within the struct
* @key: the key of the objects to iterate over
*
* This is the same as hash_for_each_possible_rcu() except that it does
* not do any RCU debugging or tracing.
*/
#define hash_for_each_possible_rcu_notrace(name, obj, member, key) \
hlist_for_each_entry_rcu_notrace(obj, \
&name[hash_min(key, HASH_BITS(name))], member)
/**
* hash_for_each_possible_safe - iterate over all possible objects hashing to the
* same bucket safe against removals
* @name: hashtable to iterate
* @obj: the type * to use as a loop cursor for each entry
* @tmp: a &struct used for temporary storage
* @member: the name of the hlist_node within the struct
* @key: the key of the objects to iterate over
*/
#define hash_for_each_possible_safe(name, obj, tmp, member, key) \
hlist_for_each_entry_safe(obj, tmp,\
&name[hash_min(key, HASH_BITS(name))], member)
#endif