LSM: shrink sizeof LSM specific portion of common_audit_data

Linus found that the gigantic size of the common audit data caused a big
perf hit on something as simple as running stat() in a loop.  This patch
requires LSMs to declare the LSM specific portion separately rather than
doing it in a union.  Thus each LSM can be responsible for shrinking their
portion and don't have to pay a penalty just because other LSMs have a
bigger space requirement.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
index 906414383022..f1f7506a464d 100644
--- a/security/apparmor/policy.c
+++ b/security/apparmor/policy.c
@@ -964,11 +964,13 @@ static int audit_policy(int op, gfp_t gfp, const char *name, const char *info,
                         int error)
 {
         struct common_audit_data sa;
+        struct apparmor_audit_data aad = {0,};
         COMMON_AUDIT_DATA_INIT(&sa, NONE);
-        sa.aad.op = op;
-        sa.aad.name = name;
-        sa.aad.info = info;
-        sa.aad.error = error;
+        sa.aad = &aad;
+        aad.op = op;
+        aad.name = name;
+        aad.info = info;
+        aad.error = error;
 
         return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp,
                         &sa, NULL);