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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
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>
441 lines
11 KiB
C
441 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Functions related to io context handling
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/slab.h>
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#include <linux/sched/task.h>
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#include "blk.h"
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/*
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* For io context allocations
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*/
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static struct kmem_cache *iocontext_cachep;
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/**
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* get_io_context - increment reference count to io_context
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* @ioc: io_context to get
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*
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* Increment reference count to @ioc.
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*/
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void get_io_context(struct io_context *ioc)
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{
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BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
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atomic_long_inc(&ioc->refcount);
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}
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EXPORT_SYMBOL(get_io_context);
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static void icq_free_icq_rcu(struct rcu_head *head)
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{
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struct io_cq *icq = container_of(head, struct io_cq, __rcu_head);
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kmem_cache_free(icq->__rcu_icq_cache, icq);
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}
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/*
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* Exit an icq. Called with ioc locked for blk-mq, and with both ioc
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* and queue locked for legacy.
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*/
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static void ioc_exit_icq(struct io_cq *icq)
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{
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struct elevator_type *et = icq->q->elevator->type;
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if (icq->flags & ICQ_EXITED)
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return;
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if (et->uses_mq && et->ops.mq.exit_icq)
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et->ops.mq.exit_icq(icq);
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else if (!et->uses_mq && et->ops.sq.elevator_exit_icq_fn)
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et->ops.sq.elevator_exit_icq_fn(icq);
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icq->flags |= ICQ_EXITED;
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}
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/*
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* Release an icq. Called with ioc locked for blk-mq, and with both ioc
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* and queue locked for legacy.
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*/
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static void ioc_destroy_icq(struct io_cq *icq)
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{
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struct io_context *ioc = icq->ioc;
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struct request_queue *q = icq->q;
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struct elevator_type *et = q->elevator->type;
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lockdep_assert_held(&ioc->lock);
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radix_tree_delete(&ioc->icq_tree, icq->q->id);
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hlist_del_init(&icq->ioc_node);
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list_del_init(&icq->q_node);
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/*
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* Both setting lookup hint to and clearing it from @icq are done
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* under queue_lock. If it's not pointing to @icq now, it never
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* will. Hint assignment itself can race safely.
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*/
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if (rcu_access_pointer(ioc->icq_hint) == icq)
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rcu_assign_pointer(ioc->icq_hint, NULL);
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ioc_exit_icq(icq);
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/*
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* @icq->q might have gone away by the time RCU callback runs
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* making it impossible to determine icq_cache. Record it in @icq.
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*/
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icq->__rcu_icq_cache = et->icq_cache;
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call_rcu(&icq->__rcu_head, icq_free_icq_rcu);
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}
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/*
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* Slow path for ioc release in put_io_context(). Performs double-lock
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* dancing to unlink all icq's and then frees ioc.
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*/
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static void ioc_release_fn(struct work_struct *work)
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{
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struct io_context *ioc = container_of(work, struct io_context,
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release_work);
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unsigned long flags;
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/*
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* Exiting icq may call into put_io_context() through elevator
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* which will trigger lockdep warning. The ioc's are guaranteed to
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* be different, use a different locking subclass here. Use
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* irqsave variant as there's no spin_lock_irq_nested().
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*/
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spin_lock_irqsave_nested(&ioc->lock, flags, 1);
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while (!hlist_empty(&ioc->icq_list)) {
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struct io_cq *icq = hlist_entry(ioc->icq_list.first,
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struct io_cq, ioc_node);
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struct request_queue *q = icq->q;
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if (spin_trylock(q->queue_lock)) {
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ioc_destroy_icq(icq);
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spin_unlock(q->queue_lock);
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} else {
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spin_unlock_irqrestore(&ioc->lock, flags);
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cpu_relax();
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spin_lock_irqsave_nested(&ioc->lock, flags, 1);
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}
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}
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spin_unlock_irqrestore(&ioc->lock, flags);
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kmem_cache_free(iocontext_cachep, ioc);
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}
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/**
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* put_io_context - put a reference of io_context
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* @ioc: io_context to put
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*
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* Decrement reference count of @ioc and release it if the count reaches
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* zero.
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*/
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void put_io_context(struct io_context *ioc)
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{
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unsigned long flags;
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bool free_ioc = false;
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if (ioc == NULL)
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return;
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BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
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/*
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* Releasing ioc requires reverse order double locking and we may
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* already be holding a queue_lock. Do it asynchronously from wq.
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*/
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if (atomic_long_dec_and_test(&ioc->refcount)) {
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spin_lock_irqsave(&ioc->lock, flags);
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if (!hlist_empty(&ioc->icq_list))
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queue_work(system_power_efficient_wq,
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&ioc->release_work);
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else
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free_ioc = true;
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spin_unlock_irqrestore(&ioc->lock, flags);
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}
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if (free_ioc)
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kmem_cache_free(iocontext_cachep, ioc);
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}
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EXPORT_SYMBOL(put_io_context);
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/**
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* put_io_context_active - put active reference on ioc
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* @ioc: ioc of interest
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*
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* Undo get_io_context_active(). If active reference reaches zero after
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* put, @ioc can never issue further IOs and ioscheds are notified.
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*/
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void put_io_context_active(struct io_context *ioc)
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{
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struct elevator_type *et;
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unsigned long flags;
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struct io_cq *icq;
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if (!atomic_dec_and_test(&ioc->active_ref)) {
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put_io_context(ioc);
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return;
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}
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/*
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* Need ioc lock to walk icq_list and q lock to exit icq. Perform
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* reverse double locking. Read comment in ioc_release_fn() for
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* explanation on the nested locking annotation.
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*/
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retry:
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spin_lock_irqsave_nested(&ioc->lock, flags, 1);
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hlist_for_each_entry(icq, &ioc->icq_list, ioc_node) {
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if (icq->flags & ICQ_EXITED)
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continue;
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et = icq->q->elevator->type;
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if (et->uses_mq) {
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ioc_exit_icq(icq);
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} else {
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if (spin_trylock(icq->q->queue_lock)) {
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ioc_exit_icq(icq);
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spin_unlock(icq->q->queue_lock);
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} else {
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spin_unlock_irqrestore(&ioc->lock, flags);
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cpu_relax();
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goto retry;
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}
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}
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}
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spin_unlock_irqrestore(&ioc->lock, flags);
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put_io_context(ioc);
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}
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/* Called by the exiting task */
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void exit_io_context(struct task_struct *task)
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{
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struct io_context *ioc;
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task_lock(task);
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ioc = task->io_context;
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task->io_context = NULL;
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task_unlock(task);
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atomic_dec(&ioc->nr_tasks);
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put_io_context_active(ioc);
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}
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static void __ioc_clear_queue(struct list_head *icq_list)
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{
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unsigned long flags;
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while (!list_empty(icq_list)) {
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struct io_cq *icq = list_entry(icq_list->next,
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struct io_cq, q_node);
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struct io_context *ioc = icq->ioc;
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spin_lock_irqsave(&ioc->lock, flags);
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ioc_destroy_icq(icq);
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spin_unlock_irqrestore(&ioc->lock, flags);
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}
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}
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/**
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* ioc_clear_queue - break any ioc association with the specified queue
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* @q: request_queue being cleared
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*
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* Walk @q->icq_list and exit all io_cq's.
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*/
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void ioc_clear_queue(struct request_queue *q)
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{
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LIST_HEAD(icq_list);
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spin_lock_irq(q->queue_lock);
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list_splice_init(&q->icq_list, &icq_list);
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if (q->mq_ops) {
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spin_unlock_irq(q->queue_lock);
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__ioc_clear_queue(&icq_list);
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} else {
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__ioc_clear_queue(&icq_list);
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spin_unlock_irq(q->queue_lock);
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}
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}
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int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
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{
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struct io_context *ioc;
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int ret;
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ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,
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node);
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if (unlikely(!ioc))
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return -ENOMEM;
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/* initialize */
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atomic_long_set(&ioc->refcount, 1);
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atomic_set(&ioc->nr_tasks, 1);
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atomic_set(&ioc->active_ref, 1);
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spin_lock_init(&ioc->lock);
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INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
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INIT_HLIST_HEAD(&ioc->icq_list);
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INIT_WORK(&ioc->release_work, ioc_release_fn);
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/*
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* Try to install. ioc shouldn't be installed if someone else
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* already did or @task, which isn't %current, is exiting. Note
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* that we need to allow ioc creation on exiting %current as exit
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* path may issue IOs from e.g. exit_files(). The exit path is
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* responsible for not issuing IO after exit_io_context().
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*/
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task_lock(task);
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if (!task->io_context &&
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(task == current || !(task->flags & PF_EXITING)))
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task->io_context = ioc;
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else
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kmem_cache_free(iocontext_cachep, ioc);
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ret = task->io_context ? 0 : -EBUSY;
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task_unlock(task);
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return ret;
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}
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/**
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* get_task_io_context - get io_context of a task
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* @task: task of interest
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* @gfp_flags: allocation flags, used if allocation is necessary
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* @node: allocation node, used if allocation is necessary
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*
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* Return io_context of @task. If it doesn't exist, it is created with
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* @gfp_flags and @node. The returned io_context has its reference count
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* incremented.
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*
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* This function always goes through task_lock() and it's better to use
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* %current->io_context + get_io_context() for %current.
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*/
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struct io_context *get_task_io_context(struct task_struct *task,
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gfp_t gfp_flags, int node)
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{
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struct io_context *ioc;
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might_sleep_if(gfpflags_allow_blocking(gfp_flags));
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do {
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task_lock(task);
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ioc = task->io_context;
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if (likely(ioc)) {
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get_io_context(ioc);
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task_unlock(task);
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return ioc;
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}
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task_unlock(task);
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} while (!create_task_io_context(task, gfp_flags, node));
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return NULL;
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}
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EXPORT_SYMBOL(get_task_io_context);
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/**
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* ioc_lookup_icq - lookup io_cq from ioc
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* @ioc: the associated io_context
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* @q: the associated request_queue
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*
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* Look up io_cq associated with @ioc - @q pair from @ioc. Must be called
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* with @q->queue_lock held.
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*/
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struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q)
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{
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struct io_cq *icq;
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lockdep_assert_held(q->queue_lock);
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/*
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* icq's are indexed from @ioc using radix tree and hint pointer,
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* both of which are protected with RCU. All removals are done
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* holding both q and ioc locks, and we're holding q lock - if we
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* find a icq which points to us, it's guaranteed to be valid.
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*/
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rcu_read_lock();
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icq = rcu_dereference(ioc->icq_hint);
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if (icq && icq->q == q)
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goto out;
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icq = radix_tree_lookup(&ioc->icq_tree, q->id);
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if (icq && icq->q == q)
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rcu_assign_pointer(ioc->icq_hint, icq); /* allowed to race */
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else
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icq = NULL;
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out:
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rcu_read_unlock();
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return icq;
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}
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EXPORT_SYMBOL(ioc_lookup_icq);
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/**
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* ioc_create_icq - create and link io_cq
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* @ioc: io_context of interest
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* @q: request_queue of interest
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* @gfp_mask: allocation mask
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*
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* Make sure io_cq linking @ioc and @q exists. If icq doesn't exist, they
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* will be created using @gfp_mask.
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*
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* The caller is responsible for ensuring @ioc won't go away and @q is
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* alive and will stay alive until this function returns.
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*/
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struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
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gfp_t gfp_mask)
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{
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struct elevator_type *et = q->elevator->type;
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struct io_cq *icq;
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/* allocate stuff */
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icq = kmem_cache_alloc_node(et->icq_cache, gfp_mask | __GFP_ZERO,
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q->node);
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if (!icq)
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return NULL;
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if (radix_tree_maybe_preload(gfp_mask) < 0) {
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kmem_cache_free(et->icq_cache, icq);
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return NULL;
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}
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icq->ioc = ioc;
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icq->q = q;
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INIT_LIST_HEAD(&icq->q_node);
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INIT_HLIST_NODE(&icq->ioc_node);
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/* lock both q and ioc and try to link @icq */
|
|
spin_lock_irq(q->queue_lock);
|
|
spin_lock(&ioc->lock);
|
|
|
|
if (likely(!radix_tree_insert(&ioc->icq_tree, q->id, icq))) {
|
|
hlist_add_head(&icq->ioc_node, &ioc->icq_list);
|
|
list_add(&icq->q_node, &q->icq_list);
|
|
if (et->uses_mq && et->ops.mq.init_icq)
|
|
et->ops.mq.init_icq(icq);
|
|
else if (!et->uses_mq && et->ops.sq.elevator_init_icq_fn)
|
|
et->ops.sq.elevator_init_icq_fn(icq);
|
|
} else {
|
|
kmem_cache_free(et->icq_cache, icq);
|
|
icq = ioc_lookup_icq(ioc, q);
|
|
if (!icq)
|
|
printk(KERN_ERR "cfq: icq link failed!\n");
|
|
}
|
|
|
|
spin_unlock(&ioc->lock);
|
|
spin_unlock_irq(q->queue_lock);
|
|
radix_tree_preload_end();
|
|
return icq;
|
|
}
|
|
|
|
static int __init blk_ioc_init(void)
|
|
{
|
|
iocontext_cachep = kmem_cache_create("blkdev_ioc",
|
|
sizeof(struct io_context), 0, SLAB_PANIC, NULL);
|
|
return 0;
|
|
}
|
|
subsys_initcall(blk_ioc_init);
|