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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>
181 lines
4.3 KiB
C
181 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Functions related to softirq rq completions
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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/interrupt.h>
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#include <linux/cpu.h>
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#include <linux/sched.h>
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#include <linux/sched/topology.h>
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#include "blk.h"
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static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
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/*
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* Softirq action handler - move entries to local list and loop over them
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* while passing them to the queue registered handler.
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*/
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static __latent_entropy void blk_done_softirq(struct softirq_action *h)
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{
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struct list_head *cpu_list, local_list;
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local_irq_disable();
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cpu_list = this_cpu_ptr(&blk_cpu_done);
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list_replace_init(cpu_list, &local_list);
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local_irq_enable();
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while (!list_empty(&local_list)) {
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struct request *rq;
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rq = list_entry(local_list.next, struct request, ipi_list);
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list_del_init(&rq->ipi_list);
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rq->q->softirq_done_fn(rq);
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}
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}
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#ifdef CONFIG_SMP
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static void trigger_softirq(void *data)
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{
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struct request *rq = data;
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unsigned long flags;
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struct list_head *list;
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local_irq_save(flags);
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list = this_cpu_ptr(&blk_cpu_done);
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list_add_tail(&rq->ipi_list, list);
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if (list->next == &rq->ipi_list)
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raise_softirq_irqoff(BLOCK_SOFTIRQ);
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local_irq_restore(flags);
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}
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/*
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* Setup and invoke a run of 'trigger_softirq' on the given cpu.
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*/
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static int raise_blk_irq(int cpu, struct request *rq)
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{
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if (cpu_online(cpu)) {
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call_single_data_t *data = &rq->csd;
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data->func = trigger_softirq;
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data->info = rq;
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data->flags = 0;
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smp_call_function_single_async(cpu, data);
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return 0;
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}
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return 1;
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}
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#else /* CONFIG_SMP */
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static int raise_blk_irq(int cpu, struct request *rq)
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{
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return 1;
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}
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#endif
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static int blk_softirq_cpu_dead(unsigned int cpu)
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{
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/*
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* If a CPU goes away, splice its entries to the current CPU
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* and trigger a run of the softirq
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*/
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local_irq_disable();
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list_splice_init(&per_cpu(blk_cpu_done, cpu),
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this_cpu_ptr(&blk_cpu_done));
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raise_softirq_irqoff(BLOCK_SOFTIRQ);
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local_irq_enable();
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return 0;
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}
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void __blk_complete_request(struct request *req)
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{
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int ccpu, cpu;
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struct request_queue *q = req->q;
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unsigned long flags;
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bool shared = false;
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BUG_ON(!q->softirq_done_fn);
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local_irq_save(flags);
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cpu = smp_processor_id();
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/*
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* Select completion CPU
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*/
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if (req->cpu != -1) {
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ccpu = req->cpu;
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if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags))
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shared = cpus_share_cache(cpu, ccpu);
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} else
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ccpu = cpu;
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/*
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* If current CPU and requested CPU share a cache, run the softirq on
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* the current CPU. One might concern this is just like
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* QUEUE_FLAG_SAME_FORCE, but actually not. blk_complete_request() is
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* running in interrupt handler, and currently I/O controller doesn't
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* support multiple interrupts, so current CPU is unique actually. This
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* avoids IPI sending from current CPU to the first CPU of a group.
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*/
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if (ccpu == cpu || shared) {
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struct list_head *list;
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do_local:
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list = this_cpu_ptr(&blk_cpu_done);
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list_add_tail(&req->ipi_list, list);
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/*
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* if the list only contains our just added request,
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* signal a raise of the softirq. If there are already
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* entries there, someone already raised the irq but it
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* hasn't run yet.
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*/
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if (list->next == &req->ipi_list)
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raise_softirq_irqoff(BLOCK_SOFTIRQ);
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} else if (raise_blk_irq(ccpu, req))
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goto do_local;
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local_irq_restore(flags);
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}
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/**
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* blk_complete_request - end I/O on a request
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* @req: the request being processed
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*
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* Description:
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* Ends all I/O on a request. It does not handle partial completions,
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* unless the driver actually implements this in its completion callback
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* through requeueing. The actual completion happens out-of-order,
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* through a softirq handler. The user must have registered a completion
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* callback through blk_queue_softirq_done().
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**/
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void blk_complete_request(struct request *req)
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{
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if (unlikely(blk_should_fake_timeout(req->q)))
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return;
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if (!blk_mark_rq_complete(req))
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__blk_complete_request(req);
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}
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EXPORT_SYMBOL(blk_complete_request);
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static __init int blk_softirq_init(void)
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{
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int i;
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for_each_possible_cpu(i)
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INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
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open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
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cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
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"block/softirq:dead", NULL,
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blk_softirq_cpu_dead);
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return 0;
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}
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subsys_initcall(blk_softirq_init);
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