The actual code does not detect 'all' with one subsystem name, which
is IMHO mutually exclusive and when an option is specified even if it
is not a subsystem name, we have to specify the 'all' option with the
other option.
eg:
 not detected : mount -t cgroup -o all,freezer cgroup /cgroup
 not flexible : mount -t cgroup -o noprefix,all cgroup /cgroup

This patch fix this and makes the code a bit more clear by replacing
'else if' indentation by 'continue' blocks in the loop.

Signed-off-by: Daniel Lezcano <daniel.lezc...@free.fr>
Signed-off-by: Serge E. Hallyn <serge.hal...@canonical.com>
Cc: Eric W. Biederman <ebied...@xmission.com>
Cc: Paul Menage <men...@google.com>
Reviewed-by: Li Zefan <l...@cn.fujitsu.com>
---
 kernel/cgroup.c |   91 +++++++++++++++++++++++++++++++++++++------------------
 1 files changed, 61 insertions(+), 30 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 0473a9a..ca2314f 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1074,7 +1074,8 @@ struct cgroup_sb_opts {
  */
 static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 {
-       char *token, *o = data ?: "all";
+       char *token, *o = data;
+       bool all_ss = false, one_ss = false;
        unsigned long mask = (unsigned long)-1;
        int i;
        bool module_pin_failed = false;
@@ -1088,26 +1089,30 @@ static int parse_cgroupfs_options(char *data, struct 
cgroup_sb_opts *opts)
        memset(opts, 0, sizeof(*opts));
 
        while ((token = strsep(&o, ",")) != NULL) {
+
                if (!*token)
                        return -EINVAL;
-               if (!strcmp(token, "all")) {
-                       /* Add all non-disabled subsystems */
-                       opts->subsys_bits = 0;
-                       for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
-                               struct cgroup_subsys *ss = subsys[i];
-                               if (ss == NULL)
-                                       continue;
-                               if (!ss->disabled)
-                                       opts->subsys_bits |= 1ul << i;
-                       }
-               } else if (!strcmp(token, "none")) {
+               if (!strcmp(token, "none")) {
                        /* Explicitly have no subsystems */
                        opts->none = true;
-               } else if (!strcmp(token, "noprefix")) {
+                       continue;
+               }
+               if (!strcmp(token, "all")) {
+                       /* Mutually exclusive option 'all' + subsystem name */
+                       if (one_ss)
+                               return -EINVAL;
+                       all_ss = true;
+                       continue;
+               }
+               if (!strcmp(token, "noprefix")) {
                        set_bit(ROOT_NOPREFIX, &opts->flags);
-               } else if (!strcmp(token, "clone_children")) {
+                       continue;
+               }
+               if (!strcmp(token, "clone_children")) {
                        set_bit(ROOT_CLONE_CHILDREN, &opts->flags);
-               } else if (!strncmp(token, "release_agent=", 14)) {
+                       continue;
+               }
+               if (!strncmp(token, "release_agent=", 14)) {
                        /* Specifying two release agents is forbidden */
                        if (opts->release_agent)
                                return -EINVAL;
@@ -1115,7 +1120,9 @@ static int parse_cgroupfs_options(char *data, struct 
cgroup_sb_opts *opts)
                                kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
                        if (!opts->release_agent)
                                return -ENOMEM;
-               } else if (!strncmp(token, "name=", 5)) {
+                       continue;
+               }
+               if (!strncmp(token, "name=", 5)) {
                        const char *name = token + 5;
                        /* Can't specify an empty name */
                        if (!strlen(name))
@@ -1137,20 +1144,44 @@ static int parse_cgroupfs_options(char *data, struct 
cgroup_sb_opts *opts)
                                              GFP_KERNEL);
                        if (!opts->name)
                                return -ENOMEM;
-               } else {
-                       struct cgroup_subsys *ss;
-                       for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
-                               ss = subsys[i];
-                               if (ss == NULL)
-                                       continue;
-                               if (!strcmp(token, ss->name)) {
-                                       if (!ss->disabled)
-                                               set_bit(i, &opts->subsys_bits);
-                                       break;
-                               }
-                       }
-                       if (i == CGROUP_SUBSYS_COUNT)
-                               return -ENOENT;
+
+                       continue;
+               }
+
+               for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+                       struct cgroup_subsys *ss = subsys[i];
+                       if (ss == NULL)
+                               continue;
+                       if (strcmp(token, ss->name))
+                               continue;
+                       if (ss->disabled)
+                               continue;
+
+                       /* Mutually exclusive option 'all' + subsystem name */
+                       if (all_ss)
+                               return -EINVAL;
+                       set_bit(i, &opts->subsys_bits);
+                       one_ss = true;
+
+                       break;
+               }
+               if (i == CGROUP_SUBSYS_COUNT)
+                       return -ENOENT;
+       }
+
+       /*
+        * If the 'all' option was specified select all the subsystems,
+        * 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)) {
+               for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+                       struct cgroup_subsys *ss = subsys[i];
+                       if (ss == NULL)
+                               continue;
+                       if (ss->disabled)
+                               continue;
+                       set_bit(i, &opts->subsys_bits);
                }
        }
 
-- 
1.7.0.4

_______________________________________________
Containers mailing list
contain...@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/containers

_______________________________________________
Devel mailing list
Devel@openvz.org
https://openvz.org/mailman/listinfo/devel

Reply via email to