-void switch_uid(struct user_struct *new_user)
-{
- struct user_struct *old_user;
-
- /* What if a process setreuid()'s and this brings the
- * new uid over his NPROC rlimit? We can check this now
- * cheaply with the new uid cache, so if it matters
- * we should be checking for it. -DaveM
- */
- old_user = current->user;
- atomic_inc(&new_user->processes);
- atomic_dec(&old_user->processes);
- switch_uid_keyring(new_user);
- current->user = new_user;
-
- /*
- * We need to synchronize with __sigqueue_alloc()
- * doing a get_uid(p->user).. If that saw the old
- * user value, we need to wait until it has exited
- * its critical region before we can free the old
- * structure.
- */
- smp_mb();
- spin_unlock_wait(¤t->sighand->siglock);
-
- free_uid(old_user);
- suid_keys(current);