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| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2016-07-01 13:44:53 -0700 |
|---|---|---|
| committer |   David Howells <dhowells@redhat.com> | 2016-07-06 10:51:14 +0100 |
| commit | 995f1405610bd8446c5be37d2ffc031a7729e406 (patch) | |
| tree | fdc1f85b9c5c60f921e94d6475296786d4c04ee9 /include/linux/rcupdate.h | |
| parent | Introduce rb_replace_node_rcu() (diff) | |
| download | linux-dev-995f1405610bd8446c5be37d2ffc031a7729e406.tar.xz linux-dev-995f1405610bd8446c5be37d2ffc031a7729e406.zip | |
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 '')
| -rw-r--r-- | include/linux/rcupdate.h | 8 |
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. |