From 47a150edc2ae734c0f4bf50aa19499e23b9a46f8 Mon Sep 17 00:00:00 2001 From: "Serge E. Hallyn" Date: Fri, 13 May 2011 04:27:54 +0100 Subject: Cache user_ns in struct cred If !CONFIG_USERNS, have current_user_ns() defined to (&init_user_ns). Get rid of _current_user_ns. This requires nsown_capable() to be defined in capability.c rather than as static inline in capability.h, so do that. Request_key needs init_user_ns defined at current_user_ns if !CONFIG_USERNS, so forward-declare that in cred.h if !CONFIG_USERNS at current_user_ns() define. Compile-tested with and without CONFIG_USERNS. Signed-off-by: Serge E. Hallyn [ This makes a huge performance difference for acl_permission_check(), up to 30%. And that is one of the hottest kernel functions for loads that are pathname-lookup heavy. ] Signed-off-by: Linus Torvalds --- include/linux/capability.h | 13 +------------ include/linux/cred.h | 10 ++++++++-- 2 files changed, 9 insertions(+), 14 deletions(-) (limited to 'include') diff --git a/include/linux/capability.h b/include/linux/capability.h index 16ee8b49a20..d4675af963f 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -546,18 +546,7 @@ extern bool has_capability_noaudit(struct task_struct *t, int cap); extern bool capable(int cap); extern bool ns_capable(struct user_namespace *ns, int cap); extern bool task_ns_capable(struct task_struct *t, int cap); - -/** - * nsown_capable - Check superior capability to one's own user_ns - * @cap: The capability in question - * - * Return true if the current task has the given superior capability - * targeted at its own user namespace. - */ -static inline bool nsown_capable(int cap) -{ - return ns_capable(current_user_ns(), cap); -} +extern bool nsown_capable(int cap); /* audit system wants to get cap info from files as well */ extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps); diff --git a/include/linux/cred.h b/include/linux/cred.h index 9aeeb0ba200..be16b61283c 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -146,6 +146,7 @@ struct cred { void *security; /* subjective LSM security */ #endif struct user_struct *user; /* real user ID subscription */ + struct user_namespace *user_ns; /* cached user->user_ns */ struct group_info *group_info; /* supplementary groups for euid/fsgid */ struct rcu_head rcu; /* RCU deletion hook */ }; @@ -354,10 +355,15 @@ static inline void put_cred(const struct cred *_cred) #define current_fsgid() (current_cred_xxx(fsgid)) #define current_cap() (current_cred_xxx(cap_effective)) #define current_user() (current_cred_xxx(user)) -#define _current_user_ns() (current_cred_xxx(user)->user_ns) #define current_security() (current_cred_xxx(security)) -extern struct user_namespace *current_user_ns(void); +#ifdef CONFIG_USER_NS +#define current_user_ns() (current_cred_xxx(user_ns)) +#else +extern struct user_namespace init_user_ns; +#define current_user_ns() (&init_user_ns) +#endif + #define current_uid_gid(_uid, _gid) \ do { \ -- cgit v1.2.3