Allows the net_cls cgroup subsystem to be compiled as a module
From: Ben Blum <bb...@andrew.cmu.edu>
This patch modifies net/sched/cls_cgroup.c to allow the net_cls subsystem to
be optionally compiled as a module instead of builtin. The cgroup_subsys
struct is moved around a bit to allow the subsys_id to be either declared as a
compile-time constant by the cgroup_subsys.h include in cgroup.h, or, if it's
a module, initialized within the struct by cgroup_load_subsys.
Signed-off-by: Ben Blum <bb...@andrew.cmu.edu>
---
net/sched/Kconfig | 5 ++++-
net/sched/cls_cgroup.c | 37 ++++++++++++++++++++++++++++---------
2 files changed, 32 insertions(+), 10 deletions(-)
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 929218a..08ff9bc 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -328,13 +328,16 @@ config NET_CLS_FLOW
module will be called cls_flow.
config NET_CLS_CGROUP
- bool "Control Group Classifier"
+ tristate "Control Group Classifier"
select NET_CLS
depends on CGROUPS
---help---
Say Y here if you want to classify packets based on the control
cgroup of their process.
+ To compile this code as a module, choose M here: the
+ module will be called cls_cgroup.
+
config NET_EMATCH
bool "Extended Matches"
select NET_CLS
diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index e4877ca..df9723b 100644
--- a/net/sched/cls_cgroup.c
+++ b/net/sched/cls_cgroup.c
@@ -24,6 +24,25 @@ struct cgroup_cls_state
u32 classid;
};
+static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
+ struct cgroup *cgrp);
+static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
+static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp);
+
+struct cgroup_subsys net_cls_subsys = {
+ .name = "net_cls",
+ .create = cgrp_create,
+ .destroy = cgrp_destroy,
+ .populate = cgrp_populate,
+#ifdef CONFIG_NET_CLS_CGROUP
+ .subsys_id = net_cls_subsys_id,
+#else
+#define net_cls_subsys_id net_cls_subsys.subsys_id
+#endif
+ .module = THIS_MODULE,
+};
+
+
static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp)
{
return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id),
@@ -79,14 +98,6 @@ static int cgrp_populate(struct cgroup_subsys *ss, struct
cgroup *cgrp)
return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files));
}
-struct cgroup_subsys net_cls_subsys = {
- .name = "net_cls",
- .create = cgrp_create,
- .destroy = cgrp_destroy,
- .populate = cgrp_populate,
- .subsys_id = net_cls_subsys_id,
-};
-
struct cls_cgroup_head
{
u32 handle;
@@ -277,12 +288,20 @@ static struct tcf_proto_ops cls_cgroup_ops __read_mostly
= {
static int __init init_cgroup_cls(void)
{
- return register_tcf_proto_ops(&cls_cgroup_ops);
+ int ret = register_tcf_proto_ops(&cls_cgroup_ops);
+ if (ret)
+ return ret;
+ ret = cgroup_load_subsys(&net_cls_subsys);
+ if (ret)
+ unregister_tcf_proto_ops(&cls_cgroup_ops);
+ return ret;
}
static void __exit exit_cgroup_cls(void)
{
unregister_tcf_proto_ops(&cls_cgroup_ops);
+ /* TODO: unload subsystem. for now, the try_module_get in load_subsys
+ * prevents us from getting here. */
}
module_init(init_cgroup_cls);
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