linux/block/blk-stat.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

206 lines
5.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef BLK_STAT_H
#define BLK_STAT_H
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/ktime.h>
#include <linux/rcupdate.h>
#include <linux/timer.h>
/*
* from upper:
* 3 bits: reserved for other usage
* 12 bits: size
* 49 bits: time
*/
#define BLK_STAT_RES_BITS 3
#define BLK_STAT_SIZE_BITS 12
#define BLK_STAT_RES_SHIFT (64 - BLK_STAT_RES_BITS)
#define BLK_STAT_SIZE_SHIFT (BLK_STAT_RES_SHIFT - BLK_STAT_SIZE_BITS)
#define BLK_STAT_TIME_MASK ((1ULL << BLK_STAT_SIZE_SHIFT) - 1)
#define BLK_STAT_SIZE_MASK \
(((1ULL << BLK_STAT_SIZE_BITS) - 1) << BLK_STAT_SIZE_SHIFT)
#define BLK_STAT_RES_MASK (~((1ULL << BLK_STAT_RES_SHIFT) - 1))
/**
* struct blk_stat_callback - Block statistics callback.
*
* A &struct blk_stat_callback is associated with a &struct request_queue. While
* @timer is active, that queue's request completion latencies are sorted into
* buckets by @bucket_fn and added to a per-cpu buffer, @cpu_stat. When the
* timer fires, @cpu_stat is flushed to @stat and @timer_fn is invoked.
*/
struct blk_stat_callback {
/*
* @list: RCU list of callbacks for a &struct request_queue.
*/
struct list_head list;
/**
* @timer: Timer for the next callback invocation.
*/
struct timer_list timer;
/**
* @cpu_stat: Per-cpu statistics buckets.
*/
struct blk_rq_stat __percpu *cpu_stat;
/**
* @bucket_fn: Given a request, returns which statistics bucket it
* should be accounted under. Return -1 for no bucket for this
* request.
*/
int (*bucket_fn)(const struct request *);
/**
* @buckets: Number of statistics buckets.
*/
unsigned int buckets;
/**
* @stat: Array of statistics buckets.
*/
struct blk_rq_stat *stat;
/**
* @fn: Callback function.
*/
void (*timer_fn)(struct blk_stat_callback *);
/**
* @data: Private pointer for the user.
*/
void *data;
struct rcu_head rcu;
};
struct blk_queue_stats *blk_alloc_queue_stats(void);
void blk_free_queue_stats(struct blk_queue_stats *);
void blk_stat_add(struct request *);
static inline u64 __blk_stat_time(u64 time)
{
return time & BLK_STAT_TIME_MASK;
}
static inline u64 blk_stat_time(struct blk_issue_stat *stat)
{
return __blk_stat_time(stat->stat);
}
static inline sector_t blk_capped_size(sector_t size)
{
return size & ((1ULL << BLK_STAT_SIZE_BITS) - 1);
}
static inline sector_t blk_stat_size(struct blk_issue_stat *stat)
{
return (stat->stat & BLK_STAT_SIZE_MASK) >> BLK_STAT_SIZE_SHIFT;
}
static inline void blk_stat_set_issue(struct blk_issue_stat *stat,
sector_t size)
{
stat->stat = (stat->stat & BLK_STAT_RES_MASK) |
(ktime_to_ns(ktime_get()) & BLK_STAT_TIME_MASK) |
(((u64)blk_capped_size(size)) << BLK_STAT_SIZE_SHIFT);
}
/* record time/size info in request but not add a callback */
void blk_stat_enable_accounting(struct request_queue *q);
/**
* blk_stat_alloc_callback() - Allocate a block statistics callback.
* @timer_fn: Timer callback function.
* @bucket_fn: Bucket callback function.
* @buckets: Number of statistics buckets.
* @data: Value for the @data field of the &struct blk_stat_callback.
*
* See &struct blk_stat_callback for details on the callback functions.
*
* Return: &struct blk_stat_callback on success or NULL on ENOMEM.
*/
struct blk_stat_callback *
blk_stat_alloc_callback(void (*timer_fn)(struct blk_stat_callback *),
int (*bucket_fn)(const struct request *),
unsigned int buckets, void *data);
/**
* blk_stat_add_callback() - Add a block statistics callback to be run on a
* request queue.
* @q: The request queue.
* @cb: The callback.
*
* Note that a single &struct blk_stat_callback can only be added to a single
* &struct request_queue.
*/
void blk_stat_add_callback(struct request_queue *q,
struct blk_stat_callback *cb);
/**
* blk_stat_remove_callback() - Remove a block statistics callback from a
* request queue.
* @q: The request queue.
* @cb: The callback.
*
* When this returns, the callback is not running on any CPUs and will not be
* called again unless readded.
*/
void blk_stat_remove_callback(struct request_queue *q,
struct blk_stat_callback *cb);
/**
* blk_stat_free_callback() - Free a block statistics callback.
* @cb: The callback.
*
* @cb may be NULL, in which case this does nothing. If it is not NULL, @cb must
* not be associated with a request queue. I.e., if it was previously added with
* blk_stat_add_callback(), it must also have been removed since then with
* blk_stat_remove_callback().
*/
void blk_stat_free_callback(struct blk_stat_callback *cb);
/**
* blk_stat_is_active() - Check if a block statistics callback is currently
* gathering statistics.
* @cb: The callback.
*/
static inline bool blk_stat_is_active(struct blk_stat_callback *cb)
{
return timer_pending(&cb->timer);
}
/**
* blk_stat_activate_nsecs() - Gather block statistics during a time window in
* nanoseconds.
* @cb: The callback.
* @nsecs: Number of nanoseconds to gather statistics for.
*
* The timer callback will be called when the window expires.
*/
static inline void blk_stat_activate_nsecs(struct blk_stat_callback *cb,
u64 nsecs)
{
mod_timer(&cb->timer, jiffies + nsecs_to_jiffies(nsecs));
}
/**
* blk_stat_activate_msecs() - Gather block statistics during a time window in
* milliseconds.
* @cb: The callback.
* @msecs: Number of milliseconds to gather statistics for.
*
* The timer callback will be called when the window expires.
*/
static inline void blk_stat_activate_msecs(struct blk_stat_callback *cb,
unsigned int msecs)
{
mod_timer(&cb->timer, jiffies + msecs_to_jiffies(msecs));
}
#endif