diff options
author | James Morris <jmorris@namei.org> | 2008-11-06 07:12:34 +0800 |
---|---|---|
committer | James Morris <jmorris@namei.org> | 2008-11-06 07:12:34 +0800 |
commit | e21e696edb498c7f7eed42ba3096f6bbe13927b6 (patch) | |
tree | 73b0bc28e45b0268f05c4b384a17bfb2140a73bc /security/device_cgroup.c | |
parent | 2f99db28af90957271a6448479c3e492ccf7c697 (diff) | |
parent | 75fa67706cce5272bcfc51ed646f2da21f3bdb6e (diff) |
Merge branch 'master' into next
Diffstat (limited to 'security/device_cgroup.c')
-rw-r--r-- | security/device_cgroup.c | 46 |
1 files changed, 8 insertions, 38 deletions
diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 46f23971f7e..5ba78701adc 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -1,5 +1,5 @@ /* - * dev_cgroup.c - device cgroup subsystem + * device_cgroup.c - device cgroup subsystem * * Copyright 2007 IBM Corp */ @@ -10,6 +10,7 @@ #include <linux/list.h> #include <linux/uaccess.h> #include <linux/seq_file.h> +#include <linux/rcupdate.h> #define ACC_MKNOD 1 #define ACC_READ 2 @@ -22,18 +23,8 @@ /* * whitelist locking rules: - * cgroup_lock() cannot be taken under dev_cgroup->lock. - * dev_cgroup->lock can be taken with or without cgroup_lock(). - * - * modifications always require cgroup_lock - * modifications to a list which is visible require the - * dev_cgroup->lock *and* cgroup_lock() - * walking the list requires dev_cgroup->lock or cgroup_lock(). - * - * reasoning: dev_whitelist_copy() needs to kmalloc, so needs - * a mutex, which the cgroup_lock() is. Since modifying - * a visible list requires both locks, either lock can be - * taken for walking the list. + * hold cgroup_lock() for update/read. + * hold rcu_read_lock() for read. */ struct dev_whitelist_item { @@ -47,7 +38,6 @@ struct dev_whitelist_item { struct dev_cgroup { struct cgroup_subsys_state css; struct list_head whitelist; - spinlock_t lock; }; static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s) @@ -84,13 +74,9 @@ static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig) struct dev_whitelist_item *wh, *tmp, *new; list_for_each_entry(wh, orig, list) { - new = kmalloc(sizeof(*wh), GFP_KERNEL); + new = kmemdup(wh, sizeof(*wh), GFP_KERNEL); if (!new) goto free_and_exit; - new->major = wh->major; - new->minor = wh->minor; - new->type = wh->type; - new->access = wh->access; list_add_tail(&new->list, dest); } @@ -107,19 +93,16 @@ free_and_exit: /* Stupid prototype - don't bother combining existing entries */ /* * called under cgroup_lock() - * since the list is visible to other tasks, we need the spinlock also */ static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, struct dev_whitelist_item *wh) { struct dev_whitelist_item *whcopy, *walk; - whcopy = kmalloc(sizeof(*whcopy), GFP_KERNEL); + whcopy = kmemdup(wh, sizeof(*wh), GFP_KERNEL); if (!whcopy) return -ENOMEM; - memcpy(whcopy, wh, sizeof(*whcopy)); - spin_lock(&dev_cgroup->lock); list_for_each_entry(walk, &dev_cgroup->whitelist, list) { if (walk->type != wh->type) continue; @@ -135,7 +118,6 @@ static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, if (whcopy != NULL) list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist); - spin_unlock(&dev_cgroup->lock); return 0; } @@ -149,14 +131,12 @@ static void whitelist_item_free(struct rcu_head *rcu) /* * called under cgroup_lock() - * since the list is visible to other tasks, we need the spinlock also */ static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup, struct dev_whitelist_item *wh) { struct dev_whitelist_item *walk, *tmp; - spin_lock(&dev_cgroup->lock); list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) { if (walk->type == DEV_ALL) goto remove; @@ -174,7 +154,6 @@ remove: call_rcu(&walk->rcu, whitelist_item_free); } } - spin_unlock(&dev_cgroup->lock); } /* @@ -214,7 +193,6 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss, } } - spin_lock_init(&dev_cgroup->lock); return &dev_cgroup->css; } @@ -330,15 +308,11 @@ static int parent_has_perm(struct dev_cgroup *childcg, { struct cgroup *pcg = childcg->css.cgroup->parent; struct dev_cgroup *parent; - int ret; if (!pcg) return 1; parent = cgroup_to_devcgroup(pcg); - spin_lock(&parent->lock); - ret = may_access_whitelist(parent, wh); - spin_unlock(&parent->lock); - return ret; + return may_access_whitelist(parent, wh); } /* @@ -357,17 +331,14 @@ static int parent_has_perm(struct dev_cgroup *childcg, static int devcgroup_update_access(struct dev_cgroup *devcgroup, int filetype, const char *buffer) { - struct dev_cgroup *cur_devcgroup; const char *b; char *endp; - int retval = 0, count; + int count; struct dev_whitelist_item wh; if (!capable(CAP_SYS_ADMIN)) return -EPERM; - cur_devcgroup = task_devcgroup(current); - memset(&wh, 0, sizeof(wh)); b = buffer; @@ -437,7 +408,6 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, } handle: - retval = 0; switch (filetype) { case DEVCG_ALLOW: if (!parent_has_perm(devcgroup, &wh)) |