path: root/kernel/capability.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/capability.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/capability.c')
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/capability.c b/kernel/capability.c
index bf0c734d0c1..32a80e08ff4 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -399,3 +399,15 @@ bool task_ns_capable(struct task_struct *t, int cap)
return ns_capable(task_cred_xxx(t, user)->user_ns, 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.
+ */
+bool nsown_capable(int cap)
+ return ns_capable(current_user_ns(), cap);