Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757197AbZC3WlR (ORCPT ); Mon, 30 Mar 2009 18:41:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752540AbZC3Wk6 (ORCPT ); Mon, 30 Mar 2009 18:40:58 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:45926 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752056AbZC3Wk6 (ORCPT ); Mon, 30 Mar 2009 18:40:58 -0400 Message-ID: <49D14A72.7010400@us.ibm.com> Date: Mon, 30 Mar 2009 15:40:50 -0700 From: Darren Hart User-Agent: Thunderbird 2.0.0.21 (X11/20090318) MIME-Version: 1.0 To: Eric Dumazet CC: linux-kernel@vger.kernel.org, Thomas Gleixner , Sripathi Kodi , Peter Zijlstra , John Stultz , Steven Rostedt , Dinakar Guniguntala , Ulrich Drepper , Ingo Molnar , Jakub Jelinek Subject: Re: [tip PATCH v6 6/8] RFC: futex: Add FUTEX_HAS_TIMEOUT flag to restart.futex.flags References: <20090330213306.606.9540.stgit@Aeon> <20090330213821.606.93755.stgit@Aeon> <49D13C50.4030601@cosmosbay.com> In-Reply-To: <49D13C50.4030601@cosmosbay.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2919 Lines: 100 Eric Dumazet wrote: Hi Eric, Thanks for the prompt review... > Darren Hart a écrit : >> - t.tv64 = restart->futex.time; >> + if (restart->futex.flags | FLAGS_HAS_TIMEOUT) { > > You probably meant : > > if (restart->futex.flags & FLAGS_HAS_TIMEOUT) Gah! You are correct. Corrected patch below. RFC: futex: Add FUTEX_HAS_TIMEOUT flag to restart.futex.flags From: Darren Hart Currently restart is only used if there is a timeout. The requeue_pi functionality requires restarting to futex_lock_pi() on signal after wakeup in futex_wait_requeue_pi() regardless of if there was a timeout or not. Using 0 for the timeout value is confusing as that could indicate an expired timer. The flag makes this explicit. Changelog: V7pre: -Corrected FLAGS_HAS_TIMEOUT flag detection logic per Eric Dumazet V6: - Initial version Signed-off-by: Darren Hart Cc: Thomas Gleixner Cc: Sripathi Kodi Cc: Peter Zijlstra Cc: John Stultz Cc: Steven Rostedt Cc: Dinakar Guniguntala Cc: Ulrich Drepper Cc: Eric Dumazet Cc: Ingo Molnar Cc: Jakub Jelinek --- kernel/futex.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index dd05803..07e314c 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1254,6 +1254,7 @@ handle_fault: */ #define FLAGS_SHARED 0x01 #define FLAGS_CLOCKRT 0x02 +#define FLAGS_HAS_TIMEOUT 0x04 static long futex_wait_restart(struct restart_block *restart); @@ -1493,7 +1494,7 @@ retry_private: restart->futex.val = val; restart->futex.time = abs_time->tv64; restart->futex.bitset = bitset; - restart->futex.flags = 0; + restart->futex.flags = FLAGS_HAS_TIMEOUT; if (fshared) restart->futex.flags |= FLAGS_SHARED; @@ -1517,13 +1518,16 @@ static long futex_wait_restart(struct restart_block *restart) { u32 __user *uaddr = (u32 __user *)restart->futex.uaddr; int fshared = 0; - ktime_t t; + ktime_t t, *tp = NULL; - t.tv64 = restart->futex.time; + if (restart->futex.flags & FLAGS_HAS_TIMEOUT) { + t.tv64 = restart->futex.time; + tp = &t; + } restart->fn = do_no_restart_syscall; if (restart->futex.flags & FLAGS_SHARED) fshared = 1; - return (long)futex_wait(uaddr, fshared, restart->futex.val, &t, + return (long)futex_wait(uaddr, fshared, restart->futex.val, tp, restart->futex.bitset, restart->futex.flags & FLAGS_CLOCKRT); } -- Darren Hart IBM Linux Technology Center Real-Time Linux Team -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/