linux/block/blk-tag.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

401 lines
10 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Functions related to tagged command queuing
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include "blk.h"
/**
* blk_queue_find_tag - find a request by its tag and queue
* @q: The request queue for the device
* @tag: The tag of the request
*
* Notes:
* Should be used when a device returns a tag and you want to match
* it with a request.
*
* no locks need be held.
**/
struct request *blk_queue_find_tag(struct request_queue *q, int tag)
{
return blk_map_queue_find_tag(q->queue_tags, tag);
}
EXPORT_SYMBOL(blk_queue_find_tag);
/**
* blk_free_tags - release a given set of tag maintenance info
* @bqt: the tag map to free
*
* Drop the reference count on @bqt and frees it when the last reference
* is dropped.
*/
void blk_free_tags(struct blk_queue_tag *bqt)
{
if (atomic_dec_and_test(&bqt->refcnt)) {
BUG_ON(find_first_bit(bqt->tag_map, bqt->max_depth) <
bqt->max_depth);
kfree(bqt->tag_index);
bqt->tag_index = NULL;
kfree(bqt->tag_map);
bqt->tag_map = NULL;
kfree(bqt);
}
}
EXPORT_SYMBOL(blk_free_tags);
/**
* __blk_queue_free_tags - release tag maintenance info
* @q: the request queue for the device
*
* Notes:
* blk_cleanup_queue() will take care of calling this function, if tagging
* has been used. So there's no need to call this directly.
**/
void __blk_queue_free_tags(struct request_queue *q)
{
struct blk_queue_tag *bqt = q->queue_tags;
if (!bqt)
return;
blk_free_tags(bqt);
q->queue_tags = NULL;
queue_flag_clear_unlocked(QUEUE_FLAG_QUEUED, q);
}
/**
* blk_queue_free_tags - release tag maintenance info
* @q: the request queue for the device
*
* Notes:
* This is used to disable tagged queuing to a device, yet leave
* queue in function.
**/
void blk_queue_free_tags(struct request_queue *q)
{
queue_flag_clear_unlocked(QUEUE_FLAG_QUEUED, q);
}
EXPORT_SYMBOL(blk_queue_free_tags);
static int
init_tag_map(struct request_queue *q, struct blk_queue_tag *tags, int depth)
{
struct request **tag_index;
unsigned long *tag_map;
int nr_ulongs;
if (q && depth > q->nr_requests * 2) {
depth = q->nr_requests * 2;
printk(KERN_ERR "%s: adjusted depth to %d\n",
__func__, depth);
}
tag_index = kzalloc(depth * sizeof(struct request *), GFP_ATOMIC);
if (!tag_index)
goto fail;
nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG;
tag_map = kzalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
if (!tag_map)
goto fail;
tags->real_max_depth = depth;
tags->max_depth = depth;
tags->tag_index = tag_index;
tags->tag_map = tag_map;
return 0;
fail:
kfree(tag_index);
return -ENOMEM;
}
static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q,
int depth, int alloc_policy)
{
struct blk_queue_tag *tags;
tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC);
if (!tags)
goto fail;
if (init_tag_map(q, tags, depth))
goto fail;
atomic_set(&tags->refcnt, 1);
tags->alloc_policy = alloc_policy;
tags->next_tag = 0;
return tags;
fail:
kfree(tags);
return NULL;
}
/**
* blk_init_tags - initialize the tag info for an external tag map
* @depth: the maximum queue depth supported
* @alloc_policy: tag allocation policy
**/
struct blk_queue_tag *blk_init_tags(int depth, int alloc_policy)
{
return __blk_queue_init_tags(NULL, depth, alloc_policy);
}
EXPORT_SYMBOL(blk_init_tags);
/**
* blk_queue_init_tags - initialize the queue tag info
* @q: the request queue for the device
* @depth: the maximum queue depth supported
* @tags: the tag to use
* @alloc_policy: tag allocation policy
*
* Queue lock must be held here if the function is called to resize an
* existing map.
**/
int blk_queue_init_tags(struct request_queue *q, int depth,
struct blk_queue_tag *tags, int alloc_policy)
{
int rc;
BUG_ON(tags && q->queue_tags && tags != q->queue_tags);
if (!tags && !q->queue_tags) {
tags = __blk_queue_init_tags(q, depth, alloc_policy);
if (!tags)
return -ENOMEM;
} else if (q->queue_tags) {
rc = blk_queue_resize_tags(q, depth);
if (rc)
return rc;
queue_flag_set(QUEUE_FLAG_QUEUED, q);
return 0;
} else
atomic_inc(&tags->refcnt);
/*
* assign it, all done
*/
q->queue_tags = tags;
queue_flag_set_unlocked(QUEUE_FLAG_QUEUED, q);
INIT_LIST_HEAD(&q->tag_busy_list);
return 0;
}
EXPORT_SYMBOL(blk_queue_init_tags);
/**
* blk_queue_resize_tags - change the queueing depth
* @q: the request queue for the device
* @new_depth: the new max command queueing depth
*
* Notes:
* Must be called with the queue lock held.
**/
int blk_queue_resize_tags(struct request_queue *q, int new_depth)
{
struct blk_queue_tag *bqt = q->queue_tags;
struct request **tag_index;
unsigned long *tag_map;
int max_depth, nr_ulongs;
if (!bqt)
return -ENXIO;
/*
* if we already have large enough real_max_depth. just
* adjust max_depth. *NOTE* as requests with tag value
* between new_depth and real_max_depth can be in-flight, tag
* map can not be shrunk blindly here.
*/
if (new_depth <= bqt->real_max_depth) {
bqt->max_depth = new_depth;
return 0;
}
/*
* Currently cannot replace a shared tag map with a new
* one, so error out if this is the case
*/
if (atomic_read(&bqt->refcnt) != 1)
return -EBUSY;
/*
* save the old state info, so we can copy it back
*/
tag_index = bqt->tag_index;
tag_map = bqt->tag_map;
max_depth = bqt->real_max_depth;
if (init_tag_map(q, bqt, new_depth))
return -ENOMEM;
memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *));
nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG;
memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long));
kfree(tag_index);
kfree(tag_map);
return 0;
}
EXPORT_SYMBOL(blk_queue_resize_tags);
/**
* blk_queue_end_tag - end tag operations for a request
* @q: the request queue for the device
* @rq: the request that has completed
*
* Description:
* Typically called when end_that_request_first() returns %0, meaning
* all transfers have been done for a request. It's important to call
* this function before end_that_request_last(), as that will put the
* request back on the free list thus corrupting the internal tag list.
**/
void blk_queue_end_tag(struct request_queue *q, struct request *rq)
{
struct blk_queue_tag *bqt = q->queue_tags;
unsigned tag = rq->tag; /* negative tags invalid */
lockdep_assert_held(q->queue_lock);
BUG_ON(tag >= bqt->real_max_depth);
list_del_init(&rq->queuelist);
rq->rq_flags &= ~RQF_QUEUED;
rq->tag = -1;
rq->internal_tag = -1;
if (unlikely(bqt->tag_index[tag] == NULL))
printk(KERN_ERR "%s: tag %d is missing\n",
__func__, tag);
bqt->tag_index[tag] = NULL;
if (unlikely(!test_bit(tag, bqt->tag_map))) {
printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
__func__, tag);
return;
}
/*
* The tag_map bit acts as a lock for tag_index[bit], so we need
* unlock memory barrier semantics.
*/
clear_bit_unlock(tag, bqt->tag_map);
}
/**
* blk_queue_start_tag - find a free tag and assign it
* @q: the request queue for the device
* @rq: the block request that needs tagging
*
* Description:
* This can either be used as a stand-alone helper, or possibly be
* assigned as the queue &prep_rq_fn (in which case &struct request
* automagically gets a tag assigned). Note that this function
* assumes that any type of request can be queued! if this is not
* true for your device, you must check the request type before
* calling this function. The request will also be removed from
* the request queue, so it's the drivers responsibility to readd
* it if it should need to be restarted for some reason.
**/
int blk_queue_start_tag(struct request_queue *q, struct request *rq)
{
struct blk_queue_tag *bqt = q->queue_tags;
unsigned max_depth;
int tag;
lockdep_assert_held(q->queue_lock);
if (unlikely((rq->rq_flags & RQF_QUEUED))) {
printk(KERN_ERR
"%s: request %p for device [%s] already tagged %d",
__func__, rq,
rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag);
BUG();
}
/*
* Protect against shared tag maps, as we may not have exclusive
* access to the tag map.
*
* We reserve a few tags just for sync IO, since we don't want
* to starve sync IO on behalf of flooding async IO.
*/
max_depth = bqt->max_depth;
if (!rq_is_sync(rq) && max_depth > 1) {
switch (max_depth) {
case 2:
max_depth = 1;
break;
case 3:
max_depth = 2;
break;
default:
max_depth -= 2;
}
if (q->in_flight[BLK_RW_ASYNC] > max_depth)
return 1;
}
do {
if (bqt->alloc_policy == BLK_TAG_ALLOC_FIFO) {
tag = find_first_zero_bit(bqt->tag_map, max_depth);
if (tag >= max_depth)
return 1;
} else {
int start = bqt->next_tag;
int size = min_t(int, bqt->max_depth, max_depth + start);
tag = find_next_zero_bit(bqt->tag_map, size, start);
if (tag >= size && start + size > bqt->max_depth) {
size = start + size - bqt->max_depth;
tag = find_first_zero_bit(bqt->tag_map, size);
}
if (tag >= size)
return 1;
}
} while (test_and_set_bit_lock(tag, bqt->tag_map));
/*
* We need lock ordering semantics given by test_and_set_bit_lock.
* See blk_queue_end_tag for details.
*/
bqt->next_tag = (tag + 1) % bqt->max_depth;
rq->rq_flags |= RQF_QUEUED;
rq->tag = tag;
bqt->tag_index[tag] = rq;
blk_start_request(rq);
list_add(&rq->queuelist, &q->tag_busy_list);
return 0;
}
EXPORT_SYMBOL(blk_queue_start_tag);
/**
* blk_queue_invalidate_tags - invalidate all pending tags
* @q: the request queue for the device
*
* Description:
* Hardware conditions may dictate a need to stop all pending requests.
* In this case, we will safely clear the block side of the tag queue and
* readd all requests to the request queue in the right order.
**/
void blk_queue_invalidate_tags(struct request_queue *q)
{
struct list_head *tmp, *n;
lockdep_assert_held(q->queue_lock);
list_for_each_safe(tmp, n, &q->tag_busy_list)
blk_requeue_request(q, list_entry_rq(tmp));
}
EXPORT_SYMBOL(blk_queue_invalidate_tags);