From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933142Ab1EXSic (ORCPT ); Tue, 24 May 2011 14:38:32 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:60946 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933073Ab1EXSiZ (ORCPT ); Tue, 24 May 2011 14:38:25 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references; b=P9Lg46i9EHdw112dP0LFDP/be3N2f9iZtjniH+N/VQMJCQNC0R3iqH1ui8w5paJDDG XaplEWMctbtHRZyOw8x9Io7xo42xoqj4OC6jhsmLX69Z3cir4FxaRBFmkJn6Zjd+i+Bt mbH/KBE1KaEjjOeOB2IjibDsBrZXvFT1LspY8= From: Tejun Heo To: oleg@redhat.com Cc: vda.linux@googlemail.com, jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, indan@nul.nu, bdonlan@gmail.com, pedro@codesourcery.com, Tejun Heo Subject: [PATCH 07/19] ptrace: use bit_waitqueue for TRAPPING instead of wait_chldexit Date: Tue, 24 May 2011 20:37:27 +0200 Message-Id: <1306262259-7285-8-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1306262259-7285-1-git-send-email-tj@kernel.org> References: <1306262259-7285-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ptracer->signal->wait_chldexit was used to wait for TRAPPING; however, ->wait_chldexit was already complicated with waker-side filtering without adding TRAPPING wait on top of it. Also, it unnecessarily made TRAPPING clearing depend on the current ptrace relationship - if the ptracee is detached, wakeup is lost. There is no reason to use signal->wait_chldexit here. We're just waiting for JOBCTL_TRAPPING bit to clear and given the relatively infrequent use of ptrace, bit_waitqueue can serve it perfectly. This patch makes JOBCTL_TRAPPING wait use bit_waitqueue instead of signal->wait_chldexit. Signed-off-by: Tejun Heo --- kernel/ptrace.c | 10 ++++++++-- kernel/signal.c | 3 +-- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/ptrace.c b/kernel/ptrace.c index b44dc43..3be5d1b 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -25,6 +25,12 @@ #include +static int ptrace_trapping_sleep_fn(void *flags) +{ + schedule(); + return 0; +} + /* * ptrace a task: make the debugger its new parent and * move it to the ptrace list. @@ -273,8 +279,8 @@ unlock_creds: mutex_unlock(&task->signal->cred_guard_mutex); out: if (wait_trap) - wait_event(current->signal->wait_chldexit, - !(task->jobctl & JOBCTL_TRAPPING)); + wait_on_bit(&task->jobctl, ilog2(JOBCTL_TRAPPING), + ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE); return retval; } diff --git a/kernel/signal.c b/kernel/signal.c index 17feedf..106b47e 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -272,8 +272,7 @@ static void task_clear_jobctl_trapping(struct task_struct *task) { if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { task->jobctl &= ~JOBCTL_TRAPPING; - __wake_up_sync_key(&task->parent->signal->wait_chldexit, - TASK_UNINTERRUPTIBLE, 1, task); + wake_up_bit(&task->jobctl, ilog2(JOBCTL_TRAPPING)); } } -- 1.7.1