The branch main has been updated by bz:
URL:
https://cgit.FreeBSD.org/src/commit/?id=3f48a0fe53ca7e001852f4a406c1bdfab1cd2f6d
commit 3f48a0fe53ca7e001852f4a406c1bdfab1cd2f6d
Author: Bjoern A. Zeeb <b...@freebsd.org>
AuthorDate: 2025-09-04 20:25:30 +0000
Commit: Bjoern A. Zeeb <b...@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_ */
