On Wed, Nov 03, 2010 at 01:54:55AM +0800, Li Zefan wrote: > On 2010年11月02日 03:15, Jiri Olsa wrote: > > hi, > > This.. > > > the rcu_dereference_check is defined as > > > > #define rcu_dereference_check(p, c) \ > > __rcu_dereference_check((p), rcu_read_lock_held() || (c), __rcu) > > > > so the caller does not need to specify rcu_read_lock_held() condition. > > > > > wbr, > > jirka > > and this should be excluded from the changelog. > > > > > > > Signed-off-by: Jiri Olsa <[email protected]> > > Reviewed-by: Li Zefan <[email protected]> > > However a nitpick: > > > --- > > include/linux/cgroup.h | 1 - > > kernel/cgroup.c | 6 ++---- > > 2 files changed, 2 insertions(+), 5 deletions(-) > ... > > @@ -4544,7 +4542,7 @@ unsigned short css_id(struct cgroup_subsys_state *css) > > * it's unchanged until freed. > > */ > > cssid = rcu_dereference_check(css->id, > > - rcu_read_lock_held() || atomic_read(&css->refcnt)); > > + atomic_read(&css->refcnt)); > > Now the 2 lines can be made into one line and still fit into 80 chars. > > > > > if (cssid) > > return cssid->id; > > @@ -4557,7 +4555,7 @@ unsigned short css_depth(struct cgroup_subsys_state > > *css) > > struct css_id *cssid; > > > > cssid = rcu_dereference_check(css->id, > > - rcu_read_lock_held() || atomic_read(&css->refcnt)); > > + atomic_read(&css->refcnt)); > > dito > > > > > if (cssid) > > return cssid->depth;
attaching changed patch wbr, jirka --- No need to specify rcu_read_lock_held() condition in rcu_dereference_check. Signed-off-by: Jiri Olsa <[email protected]> --- include/linux/cgroup.h | 1 - kernel/cgroup.c | 8 ++------ 2 files changed, 2 insertions(+), 7 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index ed4ba11..caed568 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -536,7 +536,6 @@ static inline struct cgroup_subsys_state *cgroup_subsys_state( */ #define task_subsys_state_check(task, subsys_id, __c) \ rcu_dereference_check(task->cgroups->subsys[subsys_id], \ - rcu_read_lock_held() || \ lockdep_is_held(&task->alloc_lock) || \ cgroup_lock_is_held() || (__c)) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 66a416b..a8d2221 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1687,7 +1687,6 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) { char *start; struct dentry *dentry = rcu_dereference_check(cgrp->dentry, - rcu_read_lock_held() || cgroup_lock_is_held()); if (!dentry || cgrp == dummytop) { @@ -1713,7 +1712,6 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) break; dentry = rcu_dereference_check(cgrp->dentry, - rcu_read_lock_held() || cgroup_lock_is_held()); if (!cgrp->parent) continue; @@ -4543,8 +4541,7 @@ unsigned short css_id(struct cgroup_subsys_state *css) * on this or this is under rcu_read_lock(). Once css->id is allocated, * it's unchanged until freed. */ - cssid = rcu_dereference_check(css->id, - rcu_read_lock_held() || atomic_read(&css->refcnt)); + cssid = rcu_dereference_check(css->id, atomic_read(&css->refcnt)); if (cssid) return cssid->id; @@ -4556,8 +4553,7 @@ unsigned short css_depth(struct cgroup_subsys_state *css) { struct css_id *cssid; - cssid = rcu_dereference_check(css->id, - rcu_read_lock_held() || atomic_read(&css->refcnt)); + cssid = rcu_dereference_check(css->id, atomic_read(&css->refcnt)); if (cssid) return cssid->depth; -- 1.7.1 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
