path: root/kernel/cred.c
diff options
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 /kernel/cred.c
parent381e7863d94891035a1a6b7836e9db72f9f1cba1 (diff)
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 'kernel/cred.c')
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index 5557b55048d..8093c16b84b 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -54,6 +54,7 @@ struct cred init_cred = {
.cap_effective = CAP_INIT_EFF_SET,
.cap_bset = CAP_INIT_BSET,
.user = INIT_USER,
+ .user_ns = &init_user_ns,
.group_info = &init_groups,
.tgcred = &init_tgcred,
@@ -410,6 +411,11 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
goto error_put;
+ /* cache user_ns in cred. Doesn't need a refcount because it will
+ * stay pinned by cred->user
+ */
+ new->user_ns = new->user->user_ns;
/* new threads get their own thread keyrings if their parent already
* had one */
@@ -741,12 +747,6 @@ int set_create_files_as(struct cred *new, struct inode *inode)
-struct user_namespace *current_user_ns(void)
- return _current_user_ns();
bool creds_are_invalid(const struct cred *cred)