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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-07-01 23:44:53 +0300
committerDavid Howells <dhowells@redhat.com>2016-07-06 12:51:14 +0300
commit995f1405610bd8446c5be37d2ffc031a7729e406 (patch)
treefdc1f85b9c5c60f921e94d6475296786d4c04ee9 /include/linux/rcupdate.h
parentc1adf20052d80f776849fa2c1acb472cdeb7786c (diff)
downloadlinux-995f1405610bd8446c5be37d2ffc031a7729e406.tar.xz
rcu: Suppress sparse warnings for rcu_dereference_raw()
Data structures that are used both with and without RCU protection are difficult to write in a sparse-clean manner. If you mark the relevant pointers with __rcu, sparse will complain about all non-RCU uses, but if you don't mark those pointers, sparse will complain about all RCU uses. This commit therefore suppresses sparse warnings for rcu_dereference_raw(), allowing mixed-protection data structures to avoid these warnings. Reported-by: David Howells <dhowells@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'include/linux/rcupdate.h')
-rw-r--r--include/linux/rcupdate.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 5f1533e3d032..85830e6c797b 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -611,6 +611,12 @@ static inline void rcu_preempt_sleep_check(void)
rcu_dereference_sparse(p, space); \
((typeof(*p) __force __kernel *)(p)); \
})
+#define rcu_dereference_raw(p) \
+({ \
+ /* Dependency order vs. p above. */ \
+ typeof(p) ________p1 = lockless_dereference(p); \
+ ((typeof(*p) __force __kernel *)(________p1)); \
+})
/**
* RCU_INITIALIZER() - statically initialize an RCU-protected global variable
@@ -729,8 +735,6 @@ static inline void rcu_preempt_sleep_check(void)
__rcu_dereference_check((p), (c) || rcu_read_lock_sched_held(), \
__rcu)
-#define rcu_dereference_raw(p) rcu_dereference_check(p, 1) /*@@@ needed? @@@*/
-
/*
* The tracing infrastructure traces RCU (we want that), but unfortunately
* some of the RCU checks causes tracing to lock up the system.