kernel/linux.git/include/linux/lockref.h, branch v6.19.11

lockref: add a __cond_lock annotation for lockref_put_or_lock

2025-12-09T20:58:51+00:00

Add a cond_lock annotation for lockref_put_or_lock to make sparse happy with using it. Note that for this the return value has to be double-inverted as the return value convention of lockref_put_or_lock is inverted compared to _trylock conventions expected by __cond_lock, as lockref_put_or_lock returns true when it did not need to take the lock. Signed-off-by: Christoph Hellwig Signed-off-by: Linus Torvalds

lockref: remove count argument of lockref_init

2025-02-07T09:27:25+00:00

All users of lockref_init() now initialize the count to 1, so hardcode that and remove the count argument. Reviewed-by: Christoph Hellwig Signed-off-by: Andreas Gruenbacher Link: https://lore.kernel.org/r/20250130135624.1899988-4-agruenba@redhat.com Signed-off-by: Christian Brauner

lockref: add a lockref_init helper

2025-01-16T10:48:11+00:00

Add a helper to initialize the lockdep, that is initialize the spinlock and set a value. Having to open code them isn't a big deal, but having an initializer feels right for a proper primitive. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250115094702.504610-6-hch@lst.de Signed-off-by: Christian Brauner

lockref: drop superfluous externs

2025-01-16T10:48:11+00:00

Drop the superfluous externs from the remaining prototypes in lockref.h. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250115094702.504610-5-hch@lst.de Signed-off-by: Christian Brauner

lockref: use bool for false/true returns

2025-01-16T10:48:11+00:00

Replace int used as bool with the actual bool type for return values that can only be true or false. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250115094702.504610-4-hch@lst.de Signed-off-by: Christian Brauner

lockref: remove lockref_put_not_zero

2025-01-16T10:48:10+00:00

lockref_put_not_zero is not used anywhere, and unless I'm missing something didn't end up being used used at all. Remove it. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250115094702.504610-2-hch@lst.de Signed-off-by: Christian Brauner

lockref: remove unused 'lockref_get_or_lock()' function

2022-07-03T21:40:28+00:00

Looking at the conditional lock acquire functions in the kernel due to the new sparse support (see commit 4a557a5d1a61 "sparse: introduce conditional lock acquire function attribute"), it became obvious that the lockref code has a couple of them, but they don't match the usual naming convention for the other ones, and their return value logic is also reversed. In the other very similar places, the naming pattern is '*_and_lock()' (eg 'atomic_put_and_lock()' and 'refcount_dec_and_lock()'), and the function returns true when the lock is taken. The lockref code is superficially very similar to the refcount code, only with the special "atomic wrt the embedded lock" semantics. But instead of the '*_and_lock()' naming it uses '*_or_lock()'. And instead of returning true in case it took the lock, it returns true if it *didn't* take the lock. Now, arguably the reflock code is quite logical: it really is a "either decrement _or_ lock" kind of situation - and the return value is about whether the operation succeeded without any special care needed. So despite the similarities, the differences do make some sense, and maybe it's not worth trying to unify the different conditional locking primitives in this area. But while looking at this all, it did become obvious that the 'lockref_get_or_lock()' function hasn't actually had any users for almost a decade. The only user it ever had was the shortlived 'd_rcu_to_refcount()' function, and it got removed and replaced with 'lockref_get_not_dead()' back in 2013 in commits 0d98439ea3c6 ("vfs: use lockred 'dead' flag to mark unrecoverably dead dentries") and e5c832d55588 ("vfs: fix dentry RCU to refcounting possibly sleeping dput()") In fact, that single use was removed less than a week after the whole function was introduced in commit b3abd80250c1 ("lockref: add 'lockref_get_or_lock() helper") so this function has been around for a decade, but only had a user for six days. Let's just put this mis-designed and unused function out of its misery. We can think about the naming and semantic oddities of the remaining 'lockref_put_or_lock()' later, but at least that function has users. And while the naming is different and the return value doesn't match, that function matches the whole '{atomic,refcount}_dec_and_test()' pattern much better (ie the magic happens when the count goes down to zero, not when it is incremented from zero). Signed-off-by: Linus Torvalds

lockref: Add lockref_put_not_zero

2018-04-12T16:41:19+00:00

Put a lockref unless the lockref is dead or its count would become zero. This is the same as lockref_put_or_lock except that the lock is never left held. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

lib/lockref: __lockref_is_dead can be boolean

2018-02-07T02:32:47+00:00

Make __lockref_is_dead return bool due to this function only using either true or false as its return value. No functional change. Link: http://lkml.kernel.org/r/1513266622-15860-3-git-send-email-baiyaowei@cmss.chinamobile.com Signed-off-by: Yaowei Bai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

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 Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman