From b66862f7663332aa1ecb3ebda4086360ddb8befc Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Thu, 5 Jun 2008 22:46:24 -0700 Subject: devcgroup: make a helper to convert cgroup_subsys_state to devs_cgroup This is just picking the container_of out of cgroup_to_devcgroup into a separate function. This new css_to_devcgroup will be used in the 2nd patch. Signed-off-by: Pavel Emelyanov Acked-by: Serge Hallyn Cc: Paul Menage Cc: Balbir Singh Cc: James Morris Cc: Chris Wright Cc: Stephen Smalley Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/device_cgroup.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'security/device_cgroup.c') diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 4ea583689eec..15f2f8003ba3 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -49,10 +49,14 @@ struct dev_cgroup { spinlock_t lock; }; +static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s) +{ + return container_of(s, struct dev_cgroup, css); +} + static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup) { - return container_of(cgroup_subsys_state(cgroup, devices_subsys_id), - struct dev_cgroup, css); + return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id)); } struct cgroup_subsys devices_subsys; -- cgit v1.2.3 From cc9cb219aac24ffc711566c8f372c2b3a3bf840f Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Thu, 5 Jun 2008 22:46:26 -0700 Subject: devscgroup: relax task to dev_cgroup conversion Two functions, that need to get a device_cgroup from a task (they are devcgroup_inode_permission and devcgroup_inode_mknod) make it in a strange way: They get a css_set from task, then a subsys_state from css_set, then a cgroup from the state and then a subsys_state again from the cgroup. Besides, the devices_subsys_id is read from memory, whilst there's a enum-ed constant for it. Optimize this part a bit: 1. Get the subsys_stats form the task and be done - no 2 extra dereferences, 2. Use the device_subsys_id constant, not the value from memory (i.e. one less dereference). Found while preparing 2.6.26 OpenVZ port. Signed-off-by: Pavel Emelyanov Acked-by: Serge Hallyn Acked-by: Paul Menage Cc: Balbir Singh Cc: James Morris Cc: Chris Wright Cc: Stephen Smalley Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/device_cgroup.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'security/device_cgroup.c') diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 15f2f8003ba3..f9941a769738 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -506,7 +506,6 @@ struct cgroup_subsys devices_subsys = { int devcgroup_inode_permission(struct inode *inode, int mask) { - struct cgroup *cgroup; struct dev_cgroup *dev_cgroup; struct dev_whitelist_item *wh; @@ -515,8 +514,8 @@ int devcgroup_inode_permission(struct inode *inode, int mask) return 0; if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode)) return 0; - cgroup = task_cgroup(current, devices_subsys.subsys_id); - dev_cgroup = cgroup_to_devcgroup(cgroup); + dev_cgroup = css_to_devcgroup(task_subsys_state(current, + devices_subsys_id)); if (!dev_cgroup) return 0; @@ -547,12 +546,11 @@ acc_check: int devcgroup_inode_mknod(int mode, dev_t dev) { - struct cgroup *cgroup; struct dev_cgroup *dev_cgroup; struct dev_whitelist_item *wh; - cgroup = task_cgroup(current, devices_subsys.subsys_id); - dev_cgroup = cgroup_to_devcgroup(cgroup); + dev_cgroup = css_to_devcgroup(task_subsys_state(current, + devices_subsys_id)); if (!dev_cgroup) return 0; -- cgit v1.2.3 From d1ee2971f5bd8a16bc5ecfe1b00e14b4fe407c4f Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Thu, 5 Jun 2008 22:46:28 -0700 Subject: devscgroup: make white list more compact in some cases Consider you added a 'c foo:bar r' permission to some cgroup and then (a bit later) 'c'foo:bar w' for it. After this you'll see the c foo:bar r c foo:bar w lines in a devices.list file. Another example - consider you added 10 'c foo:bar r' permissions to some cgroup (e.g. by mistake). After this you'll see 10 c foo:bar r lines in a list file. This is weird. This situation also has one more annoying consequence. Having many items in a white list makes permissions checking slower, sine it has to walk a longer list. The proposal is to merge permissions for items, that correspond to the same device. Signed-off-by: Pavel Emelyanov Acked-by: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/device_cgroup.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'security/device_cgroup.c') diff --git a/security/device_cgroup.c b/security/device_cgroup.c index f9941a769738..baf348834b66 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -106,7 +106,7 @@ free_and_exit: static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, struct dev_whitelist_item *wh) { - struct dev_whitelist_item *whcopy; + struct dev_whitelist_item *whcopy, *walk; whcopy = kmalloc(sizeof(*whcopy), GFP_KERNEL); if (!whcopy) @@ -114,7 +114,21 @@ static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, memcpy(whcopy, wh, sizeof(*whcopy)); spin_lock(&dev_cgroup->lock); - list_add_tail(&whcopy->list, &dev_cgroup->whitelist); + list_for_each_entry(walk, &dev_cgroup->whitelist, list) { + if (walk->type != wh->type) + continue; + if (walk->major != wh->major) + continue; + if (walk->minor != wh->minor) + continue; + + walk->access |= wh->access; + kfree(whcopy); + whcopy = NULL; + } + + if (whcopy != NULL) + list_add_tail(&whcopy->list, &dev_cgroup->whitelist); spin_unlock(&dev_cgroup->lock); return 0; } -- cgit v1.2.3