linux/kernel/trace/trace_stat.c
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

360 lines
7.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Infrastructure for statistic tracing (histogram output).
*
* Copyright (C) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
*
* Based on the code from trace_branch.c which is
* Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
*
*/
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/rbtree.h>
#include <linux/tracefs.h>
#include "trace_stat.h"
#include "trace.h"
/*
* List of stat red-black nodes from a tracer
* We use a such tree to sort quickly the stat
* entries from the tracer.
*/
struct stat_node {
struct rb_node node;
void *stat;
};
/* A stat session is the stats output in one file */
struct stat_session {
struct list_head session_list;
struct tracer_stat *ts;
struct rb_root stat_root;
struct mutex stat_mutex;
struct dentry *file;
};
/* All of the sessions currently in use. Each stat file embed one session */
static LIST_HEAD(all_stat_sessions);
static DEFINE_MUTEX(all_stat_sessions_mutex);
/* The root directory for all stat files */
static struct dentry *stat_dir;
static void __reset_stat_session(struct stat_session *session)
{
struct stat_node *snode, *n;
rbtree_postorder_for_each_entry_safe(snode, n, &session->stat_root, node) {
if (session->ts->stat_release)
session->ts->stat_release(snode->stat);
kfree(snode);
}
session->stat_root = RB_ROOT;
}
static void reset_stat_session(struct stat_session *session)
{
mutex_lock(&session->stat_mutex);
__reset_stat_session(session);
mutex_unlock(&session->stat_mutex);
}
static void destroy_session(struct stat_session *session)
{
tracefs_remove(session->file);
__reset_stat_session(session);
mutex_destroy(&session->stat_mutex);
kfree(session);
}
typedef int (*cmp_stat_t)(void *, void *);
static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)
{
struct rb_node **new = &(root->rb_node), *parent = NULL;
struct stat_node *data;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->stat = stat;
/*
* Figure out where to put new node
* This is a descendent sorting
*/
while (*new) {
struct stat_node *this;
int result;
this = container_of(*new, struct stat_node, node);
result = cmp(data->stat, this->stat);
parent = *new;
if (result >= 0)
new = &((*new)->rb_left);
else
new = &((*new)->rb_right);
}
rb_link_node(&data->node, parent, new);
rb_insert_color(&data->node, root);
return 0;
}
/*
* For tracers that don't provide a stat_cmp callback.
* This one will force an insertion as right-most node
* in the rbtree.
*/
static int dummy_cmp(void *p1, void *p2)
{
return -1;
}
/*
* Initialize the stat rbtree at each trace_stat file opening.
* All of these copies and sorting are required on all opening
* since the stats could have changed between two file sessions.
*/
static int stat_seq_init(struct stat_session *session)
{
struct tracer_stat *ts = session->ts;
struct rb_root *root = &session->stat_root;
void *stat;
int ret = 0;
int i;
mutex_lock(&session->stat_mutex);
__reset_stat_session(session);
if (!ts->stat_cmp)
ts->stat_cmp = dummy_cmp;
stat = ts->stat_start(ts);
if (!stat)
goto exit;
ret = insert_stat(root, stat, ts->stat_cmp);
if (ret)
goto exit;
/*
* Iterate over the tracer stat entries and store them in an rbtree.
*/
for (i = 1; ; i++) {
stat = ts->stat_next(stat, i);
/* End of insertion */
if (!stat)
break;
ret = insert_stat(root, stat, ts->stat_cmp);
if (ret)
goto exit_free_rbtree;
}
exit:
mutex_unlock(&session->stat_mutex);
return ret;
exit_free_rbtree:
__reset_stat_session(session);
mutex_unlock(&session->stat_mutex);
return ret;
}
static void *stat_seq_start(struct seq_file *s, loff_t *pos)
{
struct stat_session *session = s->private;
struct rb_node *node;
int n = *pos;
int i;
/* Prevent from tracer switch or rbtree modification */
mutex_lock(&session->stat_mutex);
/* If we are in the beginning of the file, print the headers */
if (session->ts->stat_headers) {
if (n == 0)
return SEQ_START_TOKEN;
n--;
}
node = rb_first(&session->stat_root);
for (i = 0; node && i < n; i++)
node = rb_next(node);
return node;
}
static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos)
{
struct stat_session *session = s->private;
struct rb_node *node = p;
(*pos)++;
if (p == SEQ_START_TOKEN)
return rb_first(&session->stat_root);
return rb_next(node);
}
static void stat_seq_stop(struct seq_file *s, void *p)
{
struct stat_session *session = s->private;
mutex_unlock(&session->stat_mutex);
}
static int stat_seq_show(struct seq_file *s, void *v)
{
struct stat_session *session = s->private;
struct stat_node *l = container_of(v, struct stat_node, node);
if (v == SEQ_START_TOKEN)
return session->ts->stat_headers(s);
return session->ts->stat_show(s, l->stat);
}
static const struct seq_operations trace_stat_seq_ops = {
.start = stat_seq_start,
.next = stat_seq_next,
.stop = stat_seq_stop,
.show = stat_seq_show
};
/* The session stat is refilled and resorted at each stat file opening */
static int tracing_stat_open(struct inode *inode, struct file *file)
{
int ret;
struct seq_file *m;
struct stat_session *session = inode->i_private;
ret = stat_seq_init(session);
if (ret)
return ret;
ret = seq_open(file, &trace_stat_seq_ops);
if (ret) {
reset_stat_session(session);
return ret;
}
m = file->private_data;
m->private = session;
return ret;
}
/*
* Avoid consuming memory with our now useless rbtree.
*/
static int tracing_stat_release(struct inode *i, struct file *f)
{
struct stat_session *session = i->i_private;
reset_stat_session(session);
return seq_release(i, f);
}
static const struct file_operations tracing_stat_fops = {
.open = tracing_stat_open,
.read = seq_read,
.llseek = seq_lseek,
.release = tracing_stat_release
};
static int tracing_stat_init(void)
{
struct dentry *d_tracing;
d_tracing = tracing_init_dentry();
if (IS_ERR(d_tracing))
return 0;
stat_dir = tracefs_create_dir("trace_stat", d_tracing);
if (!stat_dir)
pr_warn("Could not create tracefs 'trace_stat' entry\n");
return 0;
}
static int init_stat_file(struct stat_session *session)
{
if (!stat_dir && tracing_stat_init())
return -ENODEV;
session->file = tracefs_create_file(session->ts->name, 0644,
stat_dir,
session, &tracing_stat_fops);
if (!session->file)
return -ENOMEM;
return 0;
}
int register_stat_tracer(struct tracer_stat *trace)
{
struct stat_session *session, *node;
int ret;
if (!trace)
return -EINVAL;
if (!trace->stat_start || !trace->stat_next || !trace->stat_show)
return -EINVAL;
/* Already registered? */
mutex_lock(&all_stat_sessions_mutex);
list_for_each_entry(node, &all_stat_sessions, session_list) {
if (node->ts == trace) {
mutex_unlock(&all_stat_sessions_mutex);
return -EINVAL;
}
}
mutex_unlock(&all_stat_sessions_mutex);
/* Init the session */
session = kzalloc(sizeof(*session), GFP_KERNEL);
if (!session)
return -ENOMEM;
session->ts = trace;
INIT_LIST_HEAD(&session->session_list);
mutex_init(&session->stat_mutex);
ret = init_stat_file(session);
if (ret) {
destroy_session(session);
return ret;
}
/* Register */
mutex_lock(&all_stat_sessions_mutex);
list_add_tail(&session->session_list, &all_stat_sessions);
mutex_unlock(&all_stat_sessions_mutex);
return 0;
}
void unregister_stat_tracer(struct tracer_stat *trace)
{
struct stat_session *node, *tmp;
mutex_lock(&all_stat_sessions_mutex);
list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
if (node->ts == trace) {
list_del(&node->session_list);
destroy_session(node);
break;
}
}
mutex_unlock(&all_stat_sessions_mutex);
}