Revert "Smack: Handle io_uring kernel thread privileges"

This reverts commit 942cb357.

The io_uring PF_IO_WORKER threads no longer have PF_KTHREAD set, so no
need to special case them for credential checks.

Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

security/smack/smack_access.c

@@ -688,10 +688,9 @@ bool smack_privileged_cred(int cap, const struct cred *cred)
 bool smack_privileged(int cap)
 {
 	/*
-	 * Kernel threads may not have credentials we can use.
-	 * The io_uring kernel threads do have reliable credentials.
+	 * All kernel tasks are privileged
 	 */
-	if ((current->flags & (PF_KTHREAD | PF_IO_WORKER)) == PF_KTHREAD)
+	if (unlikely(current->flags & PF_KTHREAD))
 		return true;
 
 	return smack_privileged_cred(cap, current_cred());