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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>
300 lines
8 KiB
C
300 lines
8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/mm/page_isolation.c
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*/
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#include <linux/mm.h>
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#include <linux/page-isolation.h>
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#include <linux/pageblock-flags.h>
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#include <linux/memory.h>
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#include <linux/hugetlb.h>
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#include <linux/page_owner.h>
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#include <linux/migrate.h>
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#include "internal.h"
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#define CREATE_TRACE_POINTS
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#include <trace/events/page_isolation.h>
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static int set_migratetype_isolate(struct page *page,
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bool skip_hwpoisoned_pages)
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{
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struct zone *zone;
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unsigned long flags, pfn;
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struct memory_isolate_notify arg;
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int notifier_ret;
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int ret = -EBUSY;
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zone = page_zone(page);
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spin_lock_irqsave(&zone->lock, flags);
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pfn = page_to_pfn(page);
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arg.start_pfn = pfn;
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arg.nr_pages = pageblock_nr_pages;
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arg.pages_found = 0;
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/*
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* It may be possible to isolate a pageblock even if the
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* migratetype is not MIGRATE_MOVABLE. The memory isolation
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* notifier chain is used by balloon drivers to return the
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* number of pages in a range that are held by the balloon
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* driver to shrink memory. If all the pages are accounted for
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* by balloons, are free, or on the LRU, isolation can continue.
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* Later, for example, when memory hotplug notifier runs, these
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* pages reported as "can be isolated" should be isolated(freed)
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* by the balloon driver through the memory notifier chain.
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*/
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notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
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notifier_ret = notifier_to_errno(notifier_ret);
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if (notifier_ret)
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goto out;
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/*
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* FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
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* We just check MOVABLE pages.
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*/
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if (!has_unmovable_pages(zone, page, arg.pages_found,
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skip_hwpoisoned_pages))
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ret = 0;
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/*
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* immobile means "not-on-lru" pages. If immobile is larger than
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* removable-by-driver pages reported by notifier, we'll fail.
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*/
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out:
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if (!ret) {
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unsigned long nr_pages;
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int migratetype = get_pageblock_migratetype(page);
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set_pageblock_migratetype(page, MIGRATE_ISOLATE);
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zone->nr_isolate_pageblock++;
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nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE,
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NULL);
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__mod_zone_freepage_state(zone, -nr_pages, migratetype);
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}
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spin_unlock_irqrestore(&zone->lock, flags);
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if (!ret)
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drain_all_pages(zone);
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return ret;
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}
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static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
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{
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struct zone *zone;
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unsigned long flags, nr_pages;
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bool isolated_page = false;
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unsigned int order;
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unsigned long pfn, buddy_pfn;
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struct page *buddy;
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zone = page_zone(page);
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spin_lock_irqsave(&zone->lock, flags);
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if (!is_migrate_isolate_page(page))
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goto out;
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/*
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* Because freepage with more than pageblock_order on isolated
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* pageblock is restricted to merge due to freepage counting problem,
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* it is possible that there is free buddy page.
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* move_freepages_block() doesn't care of merge so we need other
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* approach in order to merge them. Isolation and free will make
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* these pages to be merged.
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*/
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if (PageBuddy(page)) {
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order = page_order(page);
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if (order >= pageblock_order) {
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pfn = page_to_pfn(page);
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buddy_pfn = __find_buddy_pfn(pfn, order);
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buddy = page + (buddy_pfn - pfn);
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if (pfn_valid_within(buddy_pfn) &&
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!is_migrate_isolate_page(buddy)) {
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__isolate_free_page(page, order);
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isolated_page = true;
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}
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}
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}
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/*
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* If we isolate freepage with more than pageblock_order, there
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* should be no freepage in the range, so we could avoid costly
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* pageblock scanning for freepage moving.
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*/
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if (!isolated_page) {
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nr_pages = move_freepages_block(zone, page, migratetype, NULL);
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__mod_zone_freepage_state(zone, nr_pages, migratetype);
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}
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set_pageblock_migratetype(page, migratetype);
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zone->nr_isolate_pageblock--;
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out:
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spin_unlock_irqrestore(&zone->lock, flags);
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if (isolated_page) {
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post_alloc_hook(page, order, __GFP_MOVABLE);
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__free_pages(page, order);
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}
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}
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static inline struct page *
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__first_valid_page(unsigned long pfn, unsigned long nr_pages)
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{
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int i;
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for (i = 0; i < nr_pages; i++) {
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struct page *page;
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if (!pfn_valid_within(pfn + i))
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continue;
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page = pfn_to_online_page(pfn + i);
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if (!page)
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continue;
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return page;
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}
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return NULL;
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}
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/*
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* start_isolate_page_range() -- make page-allocation-type of range of pages
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* to be MIGRATE_ISOLATE.
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* @start_pfn: The lower PFN of the range to be isolated.
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* @end_pfn: The upper PFN of the range to be isolated.
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* @migratetype: migrate type to set in error recovery.
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*
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* Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
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* the range will never be allocated. Any free pages and pages freed in the
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* future will not be allocated again.
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*
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* start_pfn/end_pfn must be aligned to pageblock_order.
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* Returns 0 on success and -EBUSY if any part of range cannot be isolated.
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*/
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int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
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unsigned migratetype, bool skip_hwpoisoned_pages)
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{
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unsigned long pfn;
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unsigned long undo_pfn;
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struct page *page;
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BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
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BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages));
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for (pfn = start_pfn;
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pfn < end_pfn;
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pfn += pageblock_nr_pages) {
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page = __first_valid_page(pfn, pageblock_nr_pages);
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if (page &&
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set_migratetype_isolate(page, skip_hwpoisoned_pages)) {
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undo_pfn = pfn;
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goto undo;
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}
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}
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return 0;
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undo:
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for (pfn = start_pfn;
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pfn < undo_pfn;
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pfn += pageblock_nr_pages) {
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struct page *page = pfn_to_online_page(pfn);
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if (!page)
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continue;
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unset_migratetype_isolate(page, migratetype);
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}
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return -EBUSY;
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}
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/*
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* Make isolated pages available again.
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*/
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int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
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unsigned migratetype)
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{
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unsigned long pfn;
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struct page *page;
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BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
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BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages));
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for (pfn = start_pfn;
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pfn < end_pfn;
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pfn += pageblock_nr_pages) {
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page = __first_valid_page(pfn, pageblock_nr_pages);
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if (!page || !is_migrate_isolate_page(page))
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continue;
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unset_migratetype_isolate(page, migratetype);
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}
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return 0;
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}
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/*
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* Test all pages in the range is free(means isolated) or not.
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* all pages in [start_pfn...end_pfn) must be in the same zone.
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* zone->lock must be held before call this.
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*
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* Returns the last tested pfn.
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*/
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static unsigned long
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__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
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bool skip_hwpoisoned_pages)
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{
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struct page *page;
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while (pfn < end_pfn) {
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if (!pfn_valid_within(pfn)) {
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pfn++;
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continue;
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}
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page = pfn_to_page(pfn);
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if (PageBuddy(page))
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/*
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* If the page is on a free list, it has to be on
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* the correct MIGRATE_ISOLATE freelist. There is no
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* simple way to verify that as VM_BUG_ON(), though.
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*/
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pfn += 1 << page_order(page);
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else if (skip_hwpoisoned_pages && PageHWPoison(page))
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/* A HWPoisoned page cannot be also PageBuddy */
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pfn++;
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else
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break;
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}
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return pfn;
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}
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/* Caller should ensure that requested range is in a single zone */
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int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
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bool skip_hwpoisoned_pages)
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{
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unsigned long pfn, flags;
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struct page *page;
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struct zone *zone;
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/*
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* Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages
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* are not aligned to pageblock_nr_pages.
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* Then we just check migratetype first.
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*/
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for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
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page = __first_valid_page(pfn, pageblock_nr_pages);
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if (page && !is_migrate_isolate_page(page))
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break;
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}
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page = __first_valid_page(start_pfn, end_pfn - start_pfn);
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if ((pfn < end_pfn) || !page)
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return -EBUSY;
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/* Check all pages are free or marked as ISOLATED */
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zone = page_zone(page);
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spin_lock_irqsave(&zone->lock, flags);
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pfn = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
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skip_hwpoisoned_pages);
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spin_unlock_irqrestore(&zone->lock, flags);
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trace_test_pages_isolated(start_pfn, end_pfn, pfn);
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return pfn < end_pfn ? -EBUSY : 0;
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}
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struct page *alloc_migrate_target(struct page *page, unsigned long private,
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int **resultp)
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{
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return new_page_nodemask(page, numa_node_id(), &node_states[N_MEMORY]);
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}
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