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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 /kernel/cred.c | |
| 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 'kernel/cred.c')
| -rw-r--r-- | kernel/cred.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/cred.c b/kernel/cred.c index 5557b55048df..8093c16b84b1 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, #ifdef CONFIG_KEYS .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; + #ifdef CONFIG_KEYS /* 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) } EXPORT_SYMBOL(set_create_files_as); -struct user_namespace *current_user_ns(void) -{ - return _current_user_ns(); -} -EXPORT_SYMBOL(current_user_ns); - #ifdef CONFIG_DEBUG_CREDENTIALS bool creds_are_invalid(const struct cred *cred) |