Merge branch 'master' into for-4.4-fixes

The following commit which went into mainline through networking tree

  3b13758f51de ("cgroups: Allow dynamically changing net_classid")

conflicts in net/core/netclassid_cgroup.c with the following pending
fix in cgroup/for-4.4-fixes.

  1f7dd3e5a6e4 ("cgroup: fix handling of multi-destination migration from subtree_control enabling")

The former separates out update_classid() from cgrp_attach() and
updates it to walk all fds of all tasks in the target css so that it
can be used from both migration and config change paths.  The latter
drops @css from cgrp_attach().

Resolve the conflict by making cgrp_attach() call update_classid()
with the css from the first task.  We can revive @tset walking in
cgrp_attach() but given that net_cls is v1 only where there always is
only one target css during migration, this is fine.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Nina Schiff <ninasc@fb.com>

1 files changed, 20 insertions, 9 deletions

diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c
index 81cb3c72efe8..d9ee8d08a3a6 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);
@@ -67,19 +67,27 @@ static int update_classid(const void *v, struct file *file, unsigned n)
 	return 0;
 }
 
-static void cgrp_attach(struct cgroup_taskset *tset)
+static void update_classid(struct cgroup_subsys_state *css, void *v)
 {
+	struct css_task_iter it;
 	struct task_struct *p;
-	struct cgroup_subsys_state *css;
-
-	cgroup_taskset_for_each(p, css, tset) {
-		struct cgroup_cls_state *cs = css_cls_state(css);
-		void *v = (void *)(unsigned long)cs->classid;
 
+	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_taskset *tset)
+{
+	struct cgroup_subsys_state *css;
+
+	cgroup_taskset_first(tset, &css);
+	update_classid(css,
+		       (void *)(unsigned long)css_cls_state(css)->classid);
 }
 
 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
@@ -90,8 +98,11 @@ 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;
 }