There is no reason to have a flags field, and then a separate
bool field just to indicate if 'none' subsystem were explicitly
requested.

Make it a flag

Signed-off-by: Glauber Costa <glom...@parallels.com>
---
 kernel/cgroup.c |   20 ++++++++++++--------
 1 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index fa405ee..e700abe 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -232,6 +232,7 @@ inline int cgroup_is_removed(const struct cgroup *cgrp)
 enum {
        ROOT_NOPREFIX, /* mounted subsystems have no named prefix */
        ROOT_CLONE_CHILDREN, /* mounted subsystems starts with clone_children */
+       ROOT_NOSUBSYS, /* explicitly asked for 'none' subsystems */
 };
 
 static int cgroup_is_releasable(const struct cgroup *cgrp)
@@ -1064,13 +1065,16 @@ struct cgroup_sb_opts {
        unsigned long flags;
        char *release_agent;
        char *name;
-       /* User explicitly requested empty subsystem */
-       bool none;
 
        struct cgroupfs_root *new_root;
 
 };
 
+static inline int opts_no_subsys(const struct cgroup_sb_opts *opts)
+{
+       return test_bit(ROOT_NOSUBSYS, &opts->flags);
+}
+
 /*
  * Convert a hierarchy specifier into a bitmask of subsystems and flags. Call
  * with cgroup_mutex held to protect the subsys[] array. This function takes
@@ -1098,7 +1102,7 @@ static int parse_cgroupfs_options(char *data, struct 
cgroup_sb_opts *opts)
                        return -EINVAL;
                if (!strcmp(token, "none")) {
                        /* Explicitly have no subsystems */
-                       opts->none = true;
+                       set_bit(ROOT_NOSUBSYS, &opts->flags);
                        continue;
                }
                if (!strcmp(token, "all")) {
@@ -1178,7 +1182,7 @@ static int parse_cgroupfs_options(char *data, struct 
cgroup_sb_opts *opts)
         * otherwise 'all, 'none' and a subsystem name options were not
         * specified, let's default to 'all'
         */
-       if (all_ss || (!all_ss && !one_ss && !opts->none)) {
+       if (all_ss || (!all_ss && !one_ss && !opts_no_subsys(opts))) {
                for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
                        struct cgroup_subsys *ss = subsys[i];
                        if (ss == NULL)
@@ -1202,7 +1206,7 @@ static int parse_cgroupfs_options(char *data, struct 
cgroup_sb_opts *opts)
 
 
        /* Can't specify "none" and some subsystems */
-       if (opts->subsys_bits && opts->none)
+       if (opts->subsys_bits && opts_no_subsys(opts))
                return -EINVAL;
 
        /*
@@ -1370,7 +1374,7 @@ static int cgroup_test_super(struct super_block *sb, void 
*data)
         * If we asked for subsystems (or explicitly for no
         * subsystems) then they must match
         */
-       if ((opts->subsys_bits || opts->none)
+       if ((opts->subsys_bits || opts_no_subsys(opts))
            && (opts->subsys_bits != root->subsys_bits))
                return 0;
 
@@ -1381,7 +1385,7 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct 
cgroup_sb_opts *opts)
 {
        struct cgroupfs_root *root;
 
-       if (!opts->subsys_bits && !opts->none)
+       if (!opts->subsys_bits && !opts_no_subsys(opts))
                return NULL;
 
        root = kzalloc(sizeof(*root), GFP_KERNEL);
@@ -1426,7 +1430,7 @@ static int cgroup_set_super(struct super_block *sb, void 
*data)
        if (!opts->new_root)
                return -EINVAL;
 
-       BUG_ON(!opts->subsys_bits && !opts->none);
+       BUG_ON(!opts->subsys_bits && !opts_no_subsys(opts));
 
        ret = set_anon_super(sb, NULL);
        if (ret)
-- 
1.7.6.4

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