From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1EE3C432C3 for ; Wed, 13 Nov 2019 21:03:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7DBCC206ED for ; Wed, 13 Nov 2019 21:03:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727484AbfKMVDd (ORCPT ); Wed, 13 Nov 2019 16:03:33 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:38867 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726812AbfKMVCT (ORCPT ); Wed, 13 Nov 2019 16:02:19 -0500 Received: from localhost ([127.0.0.1] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1iUzmL-00066g-T0; Wed, 13 Nov 2019 22:02:18 +0100 Message-Id: <20191113210104.404509322@linutronix.de> User-Agent: quilt/0.65 Date: Wed, 13 Nov 2019 21:42:47 +0100 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Andy Lutomirski , Linus Torvalds , Stephen Hemminger , Willy Tarreau , Juergen Gross , Sean Christopherson , "H. Peter Anvin" Subject: [patch V3 07/20] x86/ioperm: Avoid bitmap allocation if no permissions are set References: <20191113204240.767922595@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If ioperm() is invoked the first time and the @turn_on argument is 0, then there is no point to allocate a bitmap just to clear permissions which are not set. Signed-off-by: Thomas Gleixner --- V3: Split out from large combo patch --- arch/x86/kernel/ioport.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -36,6 +36,9 @@ long ksys_ioperm(unsigned long from, uns */ bitmap = t->io_bitmap_ptr; if (!bitmap) { + /* No point to allocate a bitmap just to clear permissions */ + if (!turn_on) + return 0; bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); if (!bitmap) return -ENOMEM;