diff options
| author | Michal Hocko <mhocko@suse.cz> | 2011-07-08 08:48:24 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-09-28 21:38:23 -0700 |
| commit | e5177ec77d503636d0b609671c9d408b981add17 (patch) | |
| tree | d6a8e7fa1790fe04caa2d6afeabd8f09f95b5555 /Documentation/RCU | |
| parent | e4cc1f22b2f4e9b0207a8cdb63e56dcf99e82d35 (diff) | |
| download | lwn-e5177ec77d503636d0b609671c9d408b981add17.tar.gz lwn-e5177ec77d503636d0b609671c9d408b981add17.zip | |
rcu: Not necessary to pass rcu_read_lock_held() to rcu_dereference_protected()
Since ca5ecddf (rcu: define __rcu address space modifier for sparse)
rcu_dereference_check() use rcu_read_lock_held() as a part of condition
automatically. Therefore, callers of rcu_dereference_check() no longer
need to pass rcu_read_lock_held() to rcu_dereference_check().
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/RCU')
| -rw-r--r-- | Documentation/RCU/lockdep.txt | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/Documentation/RCU/lockdep.txt b/Documentation/RCU/lockdep.txt index d7a49b2f6994..4998c633e20a 100644 --- a/Documentation/RCU/lockdep.txt +++ b/Documentation/RCU/lockdep.txt @@ -48,13 +48,11 @@ checking of rcu_dereference() primitives: value of the pointer itself, for example, against NULL. The rcu_dereference_check() check expression can be any boolean -expression, but would normally include one of the rcu_read_lock_held() -family of functions and a lockdep expression. However, any boolean -expression can be used. For a moderately ornate example, consider -the following: +expression, but would normally include a lockdep expression. However, +any boolean expression can be used. For a moderately ornate example, +consider the following: file = rcu_dereference_check(fdt->fd[fd], - rcu_read_lock_held() || lockdep_is_held(&files->file_lock) || atomic_read(&files->count) == 1); @@ -62,7 +60,7 @@ This expression picks up the pointer "fdt->fd[fd]" in an RCU-safe manner, and, if CONFIG_PROVE_RCU is configured, verifies that this expression is used in: -1. An RCU read-side critical section, or +1. An RCU read-side critical section (implicit), or 2. with files->file_lock held, or 3. on an unshared files_struct. |