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[net-next,RFC,09/20] net: introduce rcu_replace_pointer_rtnl

Message ID 20230124170510.316970-9-jhs@mojatatu.com (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series Introducing P4TC | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count fail Series longer than 15 patches (and no cover letter)
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3618 this patch: 3618
netdev/cc_maintainers warning 4 maintainers not CCed: liuhangbin@gmail.com idosch@nvidia.com xiangxia.m.yue@gmail.com petrm@nvidia.com
netdev/build_clang success Errors and warnings before: 919 this patch: 919
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 3758 this patch: 3758
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 18 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jamal Hadi Salim Jan. 24, 2023, 5:04 p.m. UTC 
We use rcu_replace_pointer(rcu_ptr, ptr, lockdep_rtnl_is_held()) throughout the
P4TC infrastructure code.

It may be useful for other use cases, so we create a helper.

Co-developed-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Co-developed-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
 include/linux/rtnetlink.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)
diff mbox series

Patch

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 92ad75549..56a1e80fe 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -71,6 +71,18 @@  static inline bool lockdep_rtnl_is_held(void)
 #define rcu_dereference_bh_rtnl(p)				\
 	rcu_dereference_bh_check(p, lockdep_rtnl_is_held())
 
+/**
+ * rcu_replace_pointer_rtnl - replace an RCU pointer under rtnl_lock, returning
+ * its old value
+ * @rcu_ptr: RCU pointer, whose old value is returned
+ * @ptr: regular pointer
+ *
+ * Perform a replacement under rtnl_lock, where @rcu_ptr is an RCU-annotated
+ * pointer. The old value of @rcu_ptr is returned, and @rcu_ptr is set to @ptr
+ */
+#define rcu_replace_pointer_rtnl(rcu_ptr, ptr) \
+	rcu_replace_pointer(rcu_ptr, ptr, lockdep_rtnl_is_held())
+
 /**
  * rtnl_dereference - fetch RCU pointer when updates are prevented by RTNL
  * @p: The pointer to read, prior to dereferencing