Date: Fri, 5 Sep 2025 23:29:05 GMT From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 3f48a0fe53ca - main - LinuxKPI: add DEFINE_LOCK_GUARD_0 for rcu Message-ID: <202509052329.585NT5Wn029401@gitrepo.freebsd.org>
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The branch main has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=3f48a0fe53ca7e001852f4a406c1bdfab1cd2f6d commit 3f48a0fe53ca7e001852f4a406c1bdfab1cd2f6d Author: Bjoern A. Zeeb <bz@FreeBSD.org> AuthorDate: 2025-09-04 20:25:30 +0000 Commit: Bjoern A. Zeeb <bz@FreeBSD.org> CommitDate: 2025-09-05 23:24:15 +0000 LinuxKPI: add DEFINE_LOCK_GUARD_0 for rcu This adds guard support for non-real-types like rcu locking meaning that we need to keep the lock state separately ourselves. _T is still special and needs to be updated. Given it may not be used it needs an __unused attribute (we are using the LinuxKPI __maybe_unused which indeed is more expressive in this case). Sponsored by: The FreeBSD Foundation (initially) MFC after: 3 days Reviewed by: dumbbell Differential Revision: https://reviews.freebsd.org/D52076 --- sys/compat/linuxkpi/common/include/linux/cleanup.h | 35 ++++++++++++++++++++++ .../linuxkpi/common/include/linux/rcupdate.h | 5 +++- 2 files changed, 39 insertions(+), 1 deletion(-) diff --git a/sys/compat/linuxkpi/common/include/linux/cleanup.h b/sys/compat/linuxkpi/common/include/linux/cleanup.h index 45c2a2359ddf..5bb146f082ed 100644 --- a/sys/compat/linuxkpi/common/include/linux/cleanup.h +++ b/sys/compat/linuxkpi/common/include/linux/cleanup.h @@ -55,4 +55,39 @@ #define __free(_n) __cleanup(__free_##_n) +/* + * Given this is a _0 version it should likely be broken up into parts. + * But we have no idead what a _1, _2, ... version would do different + * until we see a call. + * This is used for a not-real-type (rcu). We use a bool to "simulate" + * the lock held. Also _T still special, may not always be used, so tag + * with __unused (or better the LinuxKPI __maybe_unused). + */ +#define DEFINE_LOCK_GUARD_0(_n, _lock, _unlock, ...) \ + \ + typedef struct { \ + bool lock; \ + __VA_ARGS__; \ + } guard_ ## _n ## _t; \ + \ + static inline void \ + guard_ ## _n ## _destroy(guard_ ## _n ## _t *_T) \ + { \ + if (_T->lock) { \ + _unlock; \ + } \ + } \ + \ + static inline guard_ ## _n ## _t \ + guard_ ## _n ## _create(void) \ + { \ + guard_ ## _n ## _t _tmp; \ + guard_ ## _n ## _t *_T __maybe_unused; \ + \ + _tmp.lock = true; \ + _T = &_tmp; \ + _lock; \ + return (_tmp); \ + } + #endif /* _LINUXKPI_LINUX_CLEANUP_H */ diff --git a/sys/compat/linuxkpi/common/include/linux/rcupdate.h b/sys/compat/linuxkpi/common/include/linux/rcupdate.h index 85d766c8dbc9..4aceb7296cd6 100644 --- a/sys/compat/linuxkpi/common/include/linux/rcupdate.h +++ b/sys/compat/linuxkpi/common/include/linux/rcupdate.h @@ -1,7 +1,7 @@ /*- * Copyright (c) 2016-2017 Mellanox Technologies, Ltd. * All rights reserved. - * Copyright (c) 2024 The FreeBSD Foundation + * Copyright (c) 2024-2025 The FreeBSD Foundation * * Portions of this software were developed by Björn Zeeb * under sponsorship from the FreeBSD Foundation. @@ -35,6 +35,7 @@ #include <linux/compiler.h> #include <linux/types.h> #include <linux/kernel.h> +#include <linux/cleanup.h> #include <machine/atomic.h> @@ -162,4 +163,6 @@ void linux_synchronize_rcu(unsigned type); #define init_rcu_head_on_stack(...) #define destroy_rcu_head_on_stack(...) +DEFINE_LOCK_GUARD_0(rcu, rcu_read_lock(), rcu_read_unlock()) + #endif /* _LINUXKPI_LINUX_RCUPDATE_H_ */
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