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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>
189 lines
5.7 KiB
C
189 lines
5.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* rwsem.h: R/W semaphores, public interface
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*
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* Written by David Howells (dhowells@redhat.com).
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* Derived from asm-i386/semaphore.h
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*/
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#ifndef _LINUX_RWSEM_H
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#define _LINUX_RWSEM_H
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#include <linux/linkage.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/atomic.h>
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#include <linux/err.h>
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#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
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#include <linux/osq_lock.h>
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#endif
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struct rw_semaphore;
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#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
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#include <linux/rwsem-spinlock.h> /* use a generic implementation */
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#define __RWSEM_INIT_COUNT(name) .count = RWSEM_UNLOCKED_VALUE
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#else
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/* All arch specific implementations share the same struct */
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struct rw_semaphore {
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atomic_long_t count;
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struct list_head wait_list;
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raw_spinlock_t wait_lock;
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#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
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struct optimistic_spin_queue osq; /* spinner MCS lock */
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/*
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* Write owner. Used as a speculative check to see
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* if the owner is running on the cpu.
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*/
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struct task_struct *owner;
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lockdep_map dep_map;
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#endif
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};
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extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
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extern struct rw_semaphore *rwsem_down_read_failed_killable(struct rw_semaphore *sem);
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extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
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extern struct rw_semaphore *rwsem_down_write_failed_killable(struct rw_semaphore *sem);
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extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *);
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extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
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/* Include the arch specific part */
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#include <asm/rwsem.h>
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/* In all implementations count != 0 means locked */
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static inline int rwsem_is_locked(struct rw_semaphore *sem)
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{
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return atomic_long_read(&sem->count) != 0;
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}
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#define __RWSEM_INIT_COUNT(name) .count = ATOMIC_LONG_INIT(RWSEM_UNLOCKED_VALUE)
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#endif
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/* Common initializer macros and functions */
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
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#else
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# define __RWSEM_DEP_MAP_INIT(lockname)
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#endif
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#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
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#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED, .owner = NULL
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#else
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#define __RWSEM_OPT_INIT(lockname)
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#endif
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#define __RWSEM_INITIALIZER(name) \
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{ __RWSEM_INIT_COUNT(name), \
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.wait_list = LIST_HEAD_INIT((name).wait_list), \
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.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock) \
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__RWSEM_OPT_INIT(name) \
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__RWSEM_DEP_MAP_INIT(name) }
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#define DECLARE_RWSEM(name) \
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struct rw_semaphore name = __RWSEM_INITIALIZER(name)
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extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
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struct lock_class_key *key);
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#define init_rwsem(sem) \
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do { \
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static struct lock_class_key __key; \
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\
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__init_rwsem((sem), #sem, &__key); \
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} while (0)
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/*
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* This is the same regardless of which rwsem implementation that is being used.
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* It is just a heuristic meant to be called by somebody alreadying holding the
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* rwsem to see if somebody from an incompatible type is wanting access to the
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* lock.
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*/
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static inline int rwsem_is_contended(struct rw_semaphore *sem)
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{
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return !list_empty(&sem->wait_list);
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}
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/*
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* lock for reading
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*/
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extern void down_read(struct rw_semaphore *sem);
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/*
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* trylock for reading -- returns 1 if successful, 0 if contention
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*/
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extern int down_read_trylock(struct rw_semaphore *sem);
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/*
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* lock for writing
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*/
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extern void down_write(struct rw_semaphore *sem);
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extern int __must_check down_write_killable(struct rw_semaphore *sem);
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/*
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* trylock for writing -- returns 1 if successful, 0 if contention
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*/
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extern int down_write_trylock(struct rw_semaphore *sem);
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/*
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* release a read lock
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*/
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extern void up_read(struct rw_semaphore *sem);
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/*
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* release a write lock
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*/
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extern void up_write(struct rw_semaphore *sem);
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/*
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* downgrade write lock to read lock
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*/
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extern void downgrade_write(struct rw_semaphore *sem);
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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/*
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* nested locking. NOTE: rwsems are not allowed to recurse
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* (which occurs if the same task tries to acquire the same
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* lock instance multiple times), but multiple locks of the
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* same lock class might be taken, if the order of the locks
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* is always the same. This ordering rule can be expressed
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* to lockdep via the _nested() APIs, but enumerating the
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* subclasses that are used. (If the nesting relationship is
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* static then another method for expressing nested locking is
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* the explicit definition of lock class keys and the use of
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* lockdep_set_class() at lock initialization time.
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* See Documentation/locking/lockdep-design.txt for more details.)
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*/
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extern void down_read_nested(struct rw_semaphore *sem, int subclass);
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extern void down_write_nested(struct rw_semaphore *sem, int subclass);
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extern int down_write_killable_nested(struct rw_semaphore *sem, int subclass);
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extern void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest_lock);
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# define down_write_nest_lock(sem, nest_lock) \
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do { \
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typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \
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_down_write_nest_lock(sem, &(nest_lock)->dep_map); \
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} while (0);
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/*
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* Take/release a lock when not the owner will release it.
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*
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* [ This API should be avoided as much as possible - the
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* proper abstraction for this case is completions. ]
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*/
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extern void down_read_non_owner(struct rw_semaphore *sem);
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extern void up_read_non_owner(struct rw_semaphore *sem);
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#else
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# define down_read_nested(sem, subclass) down_read(sem)
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# define down_write_nest_lock(sem, nest_lock) down_write(sem)
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# define down_write_nested(sem, subclass) down_write(sem)
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# define down_write_killable_nested(sem, subclass) down_write_killable(sem)
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# define down_read_non_owner(sem) down_read(sem)
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# define up_read_non_owner(sem) up_read(sem)
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#endif
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#endif /* _LINUX_RWSEM_H */
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