From: Nina Schiff <nin...@fb.com>
The classid of a process is changed either when a process is moved to
or from a cgroup or when the net_cls.classid file is updated.
Previously net_cls only supported propogating these changes to the
cgroup's related sockets when a process was added or removed from the
cgroup. This means it was neccessary to remove and re-add all processes
to a cgroup in order to update its classid. This change introduces
support for doing this dynamically - i.e. when the value is changed in
the net_cls_classid file, this will also trigger an update to the
classid associated with all sockets controlled by the cgroup.
This mimics the behaviour of other cgroup subsystems.
net_prio circumvents this issue by storing an index into a table with
each socket (and so any updates to the table, don't require updating
the value associated with the socket). net_cls, however, passes the
socket the classid directly, and so this additional step is needed.
Signed-off-by: Nina Schiff <nin...@fb.com>
Signed-off-by: Tejun Heo <t...@kernel.org>
---
net/core/netclassid_cgroup.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c
index 6441f47..2e4df84 100644
--- a/net/core/netclassid_cgroup.c
+++ b/net/core/netclassid_cgroup.c
@@ -56,7 +56,7 @@ static void cgrp_css_free(struct cgroup_subsys_state *css)
kfree(css_cls_state(css));
}
-static int update_classid(const void *v, struct file *file, unsigned n)
+static int update_classid_sock(const void *v, struct file *file, unsigned n)
{
int err;
struct socket *sock = sock_from_file(file, &err);
@@ -67,18 +67,25 @@ static int update_classid(const void *v, struct file *file,
unsigned n)
return 0;
}
-static void cgrp_attach(struct cgroup_subsys_state *css,
- struct cgroup_taskset *tset)
+static void update_classid(struct cgroup_subsys_state *css, void *v)
{
- struct cgroup_cls_state *cs = css_cls_state(css);
- void *v = (void *)(unsigned long)cs->classid;
+ struct css_task_iter it;
struct task_struct *p;
- cgroup_taskset_for_each(p, tset) {
+ css_task_iter_start(css, &it);
+ while ((p = css_task_iter_next(&it))) {
task_lock(p);
- iterate_fd(p->files, 0, update_classid, v);
+ iterate_fd(p->files, 0, update_classid_sock, v);
task_unlock(p);
}
+ css_task_iter_end(&it);
+}
+
+static void cgrp_attach(struct cgroup_subsys_state *css,
+ struct cgroup_taskset *tset)
+{
+ update_classid(css,
+ (void *)(unsigned long)css_cls_state(css)->classid);
}
static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
@@ -89,8 +96,11 @@ static u64 read_classid(struct cgroup_subsys_state *css,
struct cftype *cft)
static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
u64 value)
{
- css_cls_state(css)->classid = (u32) value;
+ struct cgroup_cls_state *cs = css_cls_state(css);
+
+ cs->classid = (u32)value;
+ update_classid(css, (void *)(unsigned long)cs->classid);
return 0;
}
--
2.5.0
--
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