[PATCH 2/4] cgroup: only allow space as the separator for "cgroup.subtree_control"

[Tejun Heo <tj@kernel.org>]

I was confused that strsep() was equivalent to strtok_r() in skipping
over consecutive delimiters.  strsep() just splits at the first
occurrence of one of the delimiters which makes the parsing very
inflexible, which makes allowing multiple whitespace chars as
delimters kinda moot.  Let's just be consistently strict and require
list of tokens separated by a single space.  This is what
Documentation/cgroups/unified-hierarchy.txt describes too.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 kernel/cgroup.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 54fd12d..9066fe9 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2542,11 +2542,11 @@ static int cgroup_subtree_control_write(struct cgroup_subsys_state *dummy_css,
 	int ssid, ret;
 
 	/*
-	 * Parse input - white space separated list of subsystem names
-	 * prefixed with either + or -.
+	 * Parse input - space separated list of subsystem names prefixed
+	 * with either + or -.
 	 */
 	p = buffer;
-	while ((tok = strsep(&p, " \t\n"))) {
+	while ((tok = strsep(&p, " "))) {
 		for_each_subsys(ss, ssid) {
 			if (ss->disabled || strcmp(tok + 1, ss->name))
 				continue;
-- 
1.9.0