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| author | Eric W. Biederman <ebiederm@xmission.com> | 2012-01-09 17:24:30 -0800 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2012-01-24 16:40:28 -0800 |
| commit | 938aaa4f9249aa1519fd0db07fc72125de2df338 (patch) | |
| tree | fd248564e8988e95966cd425f3f96ce7d094ae1c | |
| parent | 3cc3e04636d603778d921854b84ae7bd34a349a2 (diff) | |
| download | linux-stable-938aaa4f9249aa1519fd0db07fc72125de2df338.tar.gz linux-stable-938aaa4f9249aa1519fd0db07fc72125de2df338.tar.bz2 linux-stable-938aaa4f9249aa1519fd0db07fc72125de2df338.zip | |
sysctl: Initial support for auto-unregistering sysctl tables.
Add nreg to ctl_table_header. When nreg drops to 0 the ctl_table_header
will be unregistered.
Factor out drop_sysctl_table from unregister_sysctl_table, and add
the logic for decrementing nreg.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| -rw-r--r-- | fs/proc/proc_sysctl.c | 28 | ||||
| -rw-r--r-- | include/linux/sysctl.h | 1 |
2 files changed, 20 insertions, 9 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 15444850b3e8..13faa48c467e 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -29,8 +29,9 @@ static struct ctl_table root_table[1]; static struct ctl_table_root sysctl_table_root; static struct ctl_table_header root_table_header = { {{.count = 1, - .ctl_table = root_table, - .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}}, + .nreg = 1, + .ctl_table = root_table, + .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}}, .root = &sysctl_table_root, .set = &sysctl_table_root.default_set, }; @@ -938,6 +939,7 @@ struct ctl_table_header *__register_sysctl_table( header->unregistering = NULL; header->root = root; header->count = 1; + header->nreg = 1; if (sysctl_check_table(path, table)) goto fail; @@ -1192,6 +1194,20 @@ struct ctl_table_header *register_sysctl_table(struct ctl_table *table) } EXPORT_SYMBOL(register_sysctl_table); +static void drop_sysctl_table(struct ctl_table_header *header) +{ + if (--header->nreg) + return; + + start_unregistering(header); + if (!--header->parent->count) { + WARN_ON(1); + kfree_rcu(header->parent, rcu); + } + if (!--header->count) + kfree_rcu(header, rcu); +} + /** * unregister_sysctl_table - unregister a sysctl table hierarchy * @header: the header returned from register_sysctl_table @@ -1224,13 +1240,7 @@ void unregister_sysctl_table(struct ctl_table_header * header) } spin_lock(&sysctl_lock); - start_unregistering(header); - if (!--header->parent->count) { - WARN_ON(1); - kfree_rcu(header->parent, rcu); - } - if (!--header->count) - kfree_rcu(header, rcu); + drop_sysctl_table(header); spin_unlock(&sysctl_lock); } EXPORT_SYMBOL(unregister_sysctl_table); diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 094bc5ccf1e2..e40b8f6e5d0e 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -1032,6 +1032,7 @@ struct ctl_table_header struct list_head ctl_entry; int used; int count; + int nreg; }; struct rcu_head rcu; }; |