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| author | Li Zefan <lizf@cn.fujitsu.com> | 2009-04-02 16:57:32 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-02 19:04:55 -0700 |
| commit | b4046f00ee7c1e5615261b496cf7309683275b29 (patch) | |
| tree | 8ef312b95b03f362f7780a37620167c54bf55e8f /security/device_cgroup.c | |
| parent | d969fbe69e07fcceb0558b35d4c75eb046041c5e (diff) | |
| download | lwn-b4046f00ee7c1e5615261b496cf7309683275b29.tar.gz lwn-b4046f00ee7c1e5615261b496cf7309683275b29.zip | |
devcgroup: avoid using cgroup_lock
There is nothing special that has to be protected by cgroup_lock,
so introduce devcgroup_mtuex for it's own use.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security/device_cgroup.c')
| -rw-r--r-- | security/device_cgroup.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 3aacd0fe7179..5fda7df19723 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -11,6 +11,7 @@ #include <linux/uaccess.h> #include <linux/seq_file.h> #include <linux/rcupdate.h> +#include <linux/mutex.h> #define ACC_MKNOD 1 #define ACC_READ 2 @@ -21,9 +22,11 @@ #define DEV_CHAR 2 #define DEV_ALL 4 /* this represents all devices */ +static DEFINE_MUTEX(devcgroup_mutex); + /* * whitelist locking rules: - * hold cgroup_lock() for update/read. + * hold devcgroup_mutex for update/read. * hold rcu_read_lock() for read. */ @@ -67,7 +70,7 @@ static int devcgroup_can_attach(struct cgroup_subsys *ss, } /* - * called under cgroup_lock() + * called under devcgroup_mutex */ static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig) { @@ -92,7 +95,7 @@ free_and_exit: /* Stupid prototype - don't bother combining existing entries */ /* - * called under cgroup_lock() + * called under devcgroup_mutex */ static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, struct dev_whitelist_item *wh) @@ -130,7 +133,7 @@ static void whitelist_item_free(struct rcu_head *rcu) } /* - * called under cgroup_lock() + * called under devcgroup_mutex */ static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup, struct dev_whitelist_item *wh) @@ -185,8 +188,10 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss, list_add(&wh->list, &dev_cgroup->whitelist); } else { parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup); + mutex_lock(&devcgroup_mutex); ret = dev_whitelist_copy(&dev_cgroup->whitelist, &parent_dev_cgroup->whitelist); + mutex_unlock(&devcgroup_mutex); if (ret) { kfree(dev_cgroup); return ERR_PTR(ret); @@ -273,7 +278,7 @@ static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft, * does the access granted to dev_cgroup c contain the access * requested in whitelist item refwh. * return 1 if yes, 0 if no. - * call with c->lock held + * call with devcgroup_mutex held */ static int may_access_whitelist(struct dev_cgroup *c, struct dev_whitelist_item *refwh) @@ -426,11 +431,11 @@ static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft, const char *buffer) { int retval; - if (!cgroup_lock_live_group(cgrp)) - return -ENODEV; + + mutex_lock(&devcgroup_mutex); retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp), cft->private, buffer); - cgroup_unlock(); + mutex_unlock(&devcgroup_mutex); return retval; } |