From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262530AbVDLS6I (ORCPT ); Tue, 12 Apr 2005 14:58:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262505AbVDLStU (ORCPT ); Tue, 12 Apr 2005 14:49:20 -0400 Received: from fire.osdl.org ([65.172.181.4]:9418 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S262231AbVDLKcx (ORCPT ); Tue, 12 Apr 2005 06:32:53 -0400 Message-Id: <200504121032.j3CAWbRa005637@shell0.pdx.osdl.net> Subject: [patch 125/198] AYSNC IO using singals other than SIGIO To: torvalds@osdl.org Cc: linux-kernel@vger.kernel.org, akpm@osdl.org, bramesh@vt.edu, roland@redhat.com From: akpm@osdl.org Date: Tue, 12 Apr 2005 03:32:30 -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Bharath Ramesh A question on sigwaitinfo based IO mechanism in multithreaded applications. I am trying to use RT signals to notify me of IO events using RT signals instead of SIGIO in a multithreaded applications. I noticed that there was some discussion on lkml during november 1999 with the subject of the discussion as "Signal driven IO". In the thread I noticed that RT signals were being delivered to the worker thread. I am running 2.6.10 kernel and I am trying to use the very same mechanism and I find that only SIGIO being propogated to the worker threads and RT signals only being propogated to the main thread and not the worker threads where I actually want them to be propogated too. On further inspection I found that the following patch which I have attached solves the problem. I am not sure if this is a bug or feature in the kernel. Roland McGrath said: This relates only to fcntl F_SETSIG, which is a Linux extension. So there is no POSIX issue. When changing various things like the normal SIGIO signalling to do group signals, I was concerned strictly with the POSIX semantics and generally avoided touching things in the domain of Linux inventions. That's why I didn't change this when I changed the call right next to it. There is no reason I can see that F_SETSIG-requested signals shouldn't use a group signal like normal SIGIO does. I'm happy to ACK this patch, there is nothing wrong with its change to the semantics in my book. But neither POSIX nor I care a whit what F_SETSIG does. Signed-off-by: Andrew Morton --- 25-akpm/fs/fcntl.c | 2 +- 1 files changed, 1 insertion(+), 1 deletion(-) diff -puN fs/fcntl.c~async-io-using-rt-signals fs/fcntl.c --- 25/fs/fcntl.c~async-io-using-rt-signals 2005-04-12 03:21:33.611027248 -0700 +++ 25-akpm/fs/fcntl.c 2005-04-12 03:21:33.614026792 -0700 @@ -437,7 +437,7 @@ static void send_sigio_to_task(struct ta else si.si_band = band_table[reason - POLL_IN]; si.si_fd = fd; - if (!send_sig_info(fown->signum, &si, p)) + if (!send_group_sig_info(fown->signum, &si, p)) break; /* fall-through: fall back on the old plain SIGIO signal */ case 0: _