linux/kernel/events
Tejun Heo 5a17f543ed cgroup: improve css_from_dir() into css_tryget_from_dir()
css_from_dir() returns the matching css (cgroup_subsys_state) given a
dentry and subsystem.  The function doesn't pin the css before
returning and requires the caller to be holding RCU read lock or
cgroup_mutex and handling pinning on the caller side.

Given that users of the function are likely to want to pin the
returned css (both existing users do) and that getting and putting
css's are very cheap, there's no reason for the interface to be tricky
like this.

Rename css_from_dir() to css_tryget_from_dir() and make it try to pin
the found css and return it only if pinning succeeded.  The callers
are updated so that they no longer do RCU locking and pinning around
the function and just use the returned css.

This will also ease converting cgroup to kernfs.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
2014-02-11 11:52:47 -05:00
..
callchain.c perf: Roll back callchain buffer refcount under the callchain mutex 2013-08-16 17:55:50 +02:00
core.c cgroup: improve css_from_dir() into css_tryget_from_dir() 2014-02-11 11:52:47 -05:00
hw_breakpoint.c hw_breakpoint: Introduce "struct bp_cpuinfo" 2013-06-20 17:58:57 +02:00
internal.h perf: Fix arch_perf_out_copy_user default 2013-11-06 12:34:25 +01:00
Makefile uprobes: Move to kernel/events/ 2012-02-22 11:08:00 +01:00
ring_buffer.c perf: Optimize ring-buffer write by depending on control dependencies 2013-12-11 15:53:22 +01:00
uprobes.c This pull request has a new feature to ftrace, namely the trace event 2014-01-22 16:35:21 -08:00