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authorSerge E. Hallyn <serge.hallyn@canonical.com>2011-05-13 04:27:54 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-13 11:45:33 -0700
commit47a150edc2ae734c0f4bf50aa19499e23b9a46f8 (patch)
treebeeba9befd531285f663559a76f6f0f7378a6c2b /include/linux/cred.h
parent381e7863d94891035a1a6b7836e9db72f9f1cba1 (diff)
downloadlinux-47a150edc2ae734c0f4bf50aa19499e23b9a46f8.tar.gz
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.h10
1 files changed, 8 insertions, 2 deletions
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 { \