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linux-next/include/linux/flex_array.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

150 lines
4.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _FLEX_ARRAY_H
#define _FLEX_ARRAY_H
#include <linux/types.h>
#include <linux/reciprocal_div.h>
#include <asm/page.h>
#define FLEX_ARRAY_PART_SIZE PAGE_SIZE
#define FLEX_ARRAY_BASE_SIZE PAGE_SIZE
struct flex_array_part;
/*
* This is meant to replace cases where an array-like
* structure has gotten too big to fit into kmalloc()
* and the developer is getting tempted to use
* vmalloc().
*/
struct flex_array {
union {
struct {
int element_size;
int total_nr_elements;
int elems_per_part;
struct reciprocal_value reciprocal_elems;
struct flex_array_part *parts[];
};
/*
* This little trick makes sure that
* sizeof(flex_array) == PAGE_SIZE
*/
char padding[FLEX_ARRAY_BASE_SIZE];
};
};
/* Number of bytes left in base struct flex_array, excluding metadata */
#define FLEX_ARRAY_BASE_BYTES_LEFT \
(FLEX_ARRAY_BASE_SIZE - offsetof(struct flex_array, parts))
/* Number of pointers in base to struct flex_array_part pages */
#define FLEX_ARRAY_NR_BASE_PTRS \
(FLEX_ARRAY_BASE_BYTES_LEFT / sizeof(struct flex_array_part *))
/* Number of elements of size that fit in struct flex_array_part */
#define FLEX_ARRAY_ELEMENTS_PER_PART(size) \
(FLEX_ARRAY_PART_SIZE / size)
/*
* Defines a statically allocated flex array and ensures its parameters are
* valid.
*/
#define DEFINE_FLEX_ARRAY(__arrayname, __element_size, __total) \
struct flex_array __arrayname = { { { \
.element_size = (__element_size), \
.total_nr_elements = (__total), \
} } }; \
static inline void __arrayname##_invalid_parameter(void) \
{ \
BUILD_BUG_ON((__total) > FLEX_ARRAY_NR_BASE_PTRS * \
FLEX_ARRAY_ELEMENTS_PER_PART(__element_size)); \
}
/**
* flex_array_alloc() - Creates a flexible array.
* @element_size: individual object size.
* @total: maximum number of objects which can be stored.
* @flags: GFP flags
*
* Return: Returns an object of structure flex_array.
*/
struct flex_array *flex_array_alloc(int element_size, unsigned int total,
gfp_t flags);
/**
* flex_array_prealloc() - Ensures that memory for the elements indexed in the
* range defined by start and nr_elements has been allocated.
* @fa: array to allocate memory to.
* @start: start address
* @nr_elements: number of elements to be allocated.
* @flags: GFP flags
*
*/
int flex_array_prealloc(struct flex_array *fa, unsigned int start,
unsigned int nr_elements, gfp_t flags);
/**
* flex_array_free() - Removes all elements of a flexible array.
* @fa: array to be freed.
*/
void flex_array_free(struct flex_array *fa);
/**
* flex_array_free_parts() - Removes all elements of a flexible array, but
* leaves the array itself in place.
* @fa: array to be emptied.
*/
void flex_array_free_parts(struct flex_array *fa);
/**
* flex_array_put() - Stores data into a flexible array.
* @fa: array where element is to be stored.
* @element_nr: position to copy, must be less than the maximum specified when
* the array was created.
* @src: data source to be copied into the array.
* @flags: GFP flags
*
* Return: Returns zero on success, a negative error code otherwise.
*/
int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
gfp_t flags);
/**
* flex_array_clear() - Clears an individual element in the array, sets the
* given element to FLEX_ARRAY_FREE.
* @element_nr: element position to clear.
* @fa: array to which element to be cleared belongs.
*
* Return: Returns zero on success, -EINVAL otherwise.
*/
int flex_array_clear(struct flex_array *fa, unsigned int element_nr);
/**
* flex_array_get() - Retrieves data into a flexible array.
*
* @element_nr: Element position to retrieve data from.
* @fa: array from which data is to be retrieved.
*
* Return: Returns a pointer to the data element, or NULL if that
* particular element has never been allocated.
*/
void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
/**
* flex_array_shrink() - Reduces the allocated size of an array.
* @fa: array to shrink.
*
* Return: Returns number of pages of memory actually freed.
*
*/
int flex_array_shrink(struct flex_array *fa);
#define flex_array_put_ptr(fa, nr, src, gfp) \
flex_array_put(fa, nr, (void *)&(src), gfp)
void *flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr);
#endif /* _FLEX_ARRAY_H */