netcls_cgroup: introduce cgroup_cls_state->is_local
cs->is_local will be used to indicate whether the cgroup has its own
configuration or inherited from the parent. It's set when classid is
configured by writing a positive value to cgroup file
"net_cls.classid" and cleared when a negative value is written.
is_local is visible to userland via cgroup file "net_cls.is_local" so
that userland can know whether a cgroup has its config or not.
This patch doesn't yet change hierarchy behavior. The next patch will
use is_local to implement proper hierarchy.
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/include/net/cls_cgroup.h b/include/net/cls_cgroup.h
index b6a6eeb..5759d98 100644
--- a/include/net/cls_cgroup.h
+++ b/include/net/cls_cgroup.h
@@ -22,6 +22,7 @@
{
struct cgroup_subsys_state css;
u32 classid;
+ bool is_local; /* class id is explicitly configured for this cgroup */
};
extern void sock_update_classid(struct sock *sk);
diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index 80a80c4..6e3ef64 100644
--- a/net/sched/cls_cgroup.c
+++ b/net/sched/cls_cgroup.c
@@ -70,19 +70,36 @@
return cgrp_cls_state(cgrp)->classid;
}
-static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
+static int write_classid(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
{
+ struct cgroup_cls_state *cs = cgrp_cls_state(cgrp);
+ s64 v;
+
+ if (sscanf(buf, "%lld", &v) != 1)
+ return -EINVAL;
+
mutex_lock(&netcls_mutex);
- cgrp_cls_state(cgrp)->classid = (u32) value;
+ cs->classid = clamp_val(v, 0, UINT_MAX);
+ cs->is_local = v >= 0;
mutex_unlock(&netcls_mutex);
return 0;
}
+static u64 read_is_local(struct cgroup *cgrp, struct cftype *cft)
+{
+ return cgrp_cls_state(cgrp)->is_local;
+}
+
static struct cftype ss_files[] = {
{
.name = "classid",
.read_u64 = read_classid,
- .write_u64 = write_classid,
+ .write_string = write_classid,
+ },
+ {
+ .name = "is_local",
+ .read_u64 = read_is_local,
},
{ } /* terminate */
};
