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| author | Serge E. Hallyn <serge.hallyn@canonical.com> | 2011-05-13 04:27:54 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-13 11:45:33 -0700 |
| commit | 47a150edc2ae734c0f4bf50aa19499e23b9a46f8 (patch) | |
| tree | beeba9befd531285f663559a76f6f0f7378a6c2b /include/linux/cred.h | |
| parent | 381e7863d94891035a1a6b7836e9db72f9f1cba1 (diff) | |
| download | lwn-47a150edc2ae734c0f4bf50aa19499e23b9a46f8.tar.gz lwn-47a150edc2ae734c0f4bf50aa19499e23b9a46f8.zip | |
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 <serge.hallyn@canonical.com>
[ 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 <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/cred.h')
| -rw-r--r-- | include/linux/cred.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h index 9aeeb0ba2003..be16b61283cc 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 { \ |