Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936922AbZDCUmM (ORCPT ); Fri, 3 Apr 2009 16:42:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S936923AbZDCUkc (ORCPT ); Fri, 3 Apr 2009 16:40:32 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:43882 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936907AbZDCUk3 (ORCPT ); Fri, 3 Apr 2009 16:40:29 -0400 From: Darren Hart Subject: [tip PATCH v7 6/9] RFC: futex: Add FUTEX_HAS_TIMEOUT flag to restart.futex.flags To: linux-kernel@vger.kernel.org Cc: Thomas Gleixner , Sripathi Kodi , Peter Zijlstra , John Stultz , Steven Rostedt , Dinakar Guniguntala , Ulrich Drepper , Eric Dumazet , Ingo Molnar , Jakub Jelinek , Darren Hart , Thomas Gleixner , Sripathi Kodi , Peter Zijlstra , John Stultz , Steven Rostedt , Dinakar Guniguntala , Ulrich Drepper , Eric Dumazet , Ingo Molnar , Jakub Jelinek Date: Fri, 03 Apr 2009 13:40:22 -0700 Message-ID: <20090403204022.9772.35322.stgit@Aeon> In-Reply-To: <20090403203832.9772.21410.stgit@Aeon> References: <20090403203832.9772.21410.stgit@Aeon> User-Agent: StGIT/0.14.2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2633 Lines: 75 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. While the check is not technically needed in futex_wait_restart(), doing so makes the code consistent with and will avoid confusion should the need arise to restart wait without a timeout. Changelog: V7: -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 c2b58d8..04e5431 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1252,6 +1252,7 @@ handle_fault: */ #define FLAGS_SHARED 0x01 #define FLAGS_CLOCKRT 0x02 +#define FLAGS_HAS_TIMEOUT 0x04 static long futex_wait_restart(struct restart_block *restart); @@ -1486,7 +1487,7 @@ 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; @@ -1510,13 +1511,16 @@ 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); } -- 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/