From: "Joel Fernandes (Google)" <[email protected]>
Upstream commit:
commit 28875945ba98d1b47a8a706812b6494d165bb0a0
Author: Joel Fernandes (Google) <[email protected]>
Date: Tue Jul 16 18:12:22 2019 -0400
rcu: Add support for consolidated-RCU reader checking
This commit adds RCU-reader checks to list_for_each_entry_rcu() and
hlist_for_each_entry_rcu(). These checks are optional, and are indicated
by a lockdep expression passed to a new optional argument to these two
macros. If this optional lockdep expression is omitted, these two macros
act as before, checking for an RCU read-side critical section.
Signed-off-by: Joel Fernandes (Google) <[email protected]>
[ paulmck: Update to eliminate return within macro and update comment. ]
Signed-off-by: Paul E. McKenney <[email protected]>
Backport portion of upstream commit for hlist_for_each_entry_rcu() macro
so that it can be used in following bug fix.
Cc: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Greg Rose <[email protected]>
---
datapath/linux/compat/include/linux/rculist.h | 23 +++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/datapath/linux/compat/include/linux/rculist.h
b/datapath/linux/compat/include/linux/rculist.h
index 8df8ad8a2..40fd5e171 100644
--- a/datapath/linux/compat/include/linux/rculist.h
+++ b/datapath/linux/compat/include/linux/rculist.h
@@ -9,9 +9,28 @@
#define hlist_pprev_rcu(node) (*((struct hlist_node __rcu
**)((node)->pprev)))
#endif
+/*
+ * Check during list traversal that we are within an RCU reader
+ */
+
+#define check_arg_count_one(dummy)
+
+#ifdef CONFIG_PROVE_RCU_LIST
+#define __list_check_rcu(dummy, cond, extra...)
\
+ ({ \
+ check_arg_count_one(extra); \
+ RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \
+ "RCU-list traversed in non-reader section!"); \
+ })
+#else
+#define __list_check_rcu(dummy, cond, extra...)
\
+ ({ check_arg_count_one(extra); })
+#endif
+
#undef hlist_for_each_entry_rcu
-#define hlist_for_each_entry_rcu(pos, head, member) \
- for (pos = hlist_entry_safe
(rcu_dereference_raw(hlist_first_rcu(head)),\
+#define hlist_for_each_entry_rcu(pos, head, member, cond...) \
+ for (__list_check_rcu(dummy, ## cond, 0), \
+ pos = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),\
typeof(*(pos)), member); \
pos; \
pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\
--
2.17.1
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