Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751363AbWINWK0 (ORCPT ); Thu, 14 Sep 2006 18:10:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751362AbWINWK0 (ORCPT ); Thu, 14 Sep 2006 18:10:26 -0400 Received: from MAIL.13thfloor.at ([213.145.232.33]:53418 "EHLO MAIL.13thfloor.at") by vger.kernel.org with ESMTP id S1751361AbWINWKZ (ORCPT ); Thu, 14 Sep 2006 18:10:25 -0400 Date: Fri, 15 Sep 2006 00:10:24 +0200 From: Herbert Poetzl To: Cedric Le Goater Cc: "Eric W. Biederman" , containers@lists.osdl.org, Linux Kernel Mailing List , v4l-dvb-maintainer@linuxtv.org, Andrew Morton , Andrew de Quincey Subject: Re: [PATCH/RFC] kthread API conversion for dvb_frontend and av7110 Message-ID: <20060914221024.GB26916@MAIL.13thfloor.at> Mail-Followup-To: Cedric Le Goater , "Eric W. Biederman" , containers@lists.osdl.org, Linux Kernel Mailing List , v4l-dvb-maintainer@linuxtv.org, Andrew Morton , Andrew de Quincey References: <45019CC3.2030709@fr.ibm.com> <450537B6.1020509@fr.ibm.com> <45056D3E.6040702@fr.ibm.com> <20060912110559.GD23808@MAIL.13thfloor.at> <20060914200103.GA8448@MAIL.13thfloor.at> <4509C4A5.5030600@fr.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4509C4A5.5030600@fr.ibm.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4171 Lines: 133 On Thu, Sep 14, 2006 at 11:07:49PM +0200, Cedric Le Goater wrote: > Herbert Poetzl wrote: > > Okay, as I promised, I had a first shot at the > > dvb kernel_thread to kthread API port, and here > > is the result, which is running fine here since > > yesterday, including module load/unload and > > software suspend (which doesn't work as expected > > with or without this patch :), > > So you have such an hardware ? yes, I do .. that's how I tested it :) > [ ... ] > > > @@ -600,7 +595,6 @@ static int dvb_frontend_thread(void *dat > > > > static void dvb_frontend_stop(struct dvb_frontend *fe) > > { > > - unsigned long ret; > > struct dvb_frontend_private *fepriv = fe->frontend_priv; > > > > dprintk ("%s\n", __FUNCTION__); > > @@ -608,33 +602,17 @@ static void dvb_frontend_stop(struct dvb > > fepriv->exit = 1; > > do we still need the ->exit flag now that we are using kthread_stop() ? > same question for ->wakeup ? probably not, but I didn't want to change too much on the first try, especially I'd appreciate some feedback to this from the maintainer(s) > > mb(); > > > > - if (!fepriv->thread_pid) > > - return; > > - > > - /* check if the thread is really alive */ > > - if (kill_proc(fepriv->thread_pid, 0, 1) == -ESRCH) { > > - printk("dvb_frontend_stop: thread PID %d already died\n", > > - fepriv->thread_pid); > > - /* make sure the mutex was not held by the thread */ > > - init_MUTEX (&fepriv->sem); > > + if (!fepriv->thread) > > return; > > - } > > - > > - /* wake up the frontend thread, so it notices that fe->exit == 1 */ > > - dvb_frontend_wakeup(fe); > > > > - /* wait until the frontend thread has exited */ > > - ret = wait_event_interruptible(fepriv->wait_queue,0 == fepriv->thread_pid); > > - if (-ERESTARTSYS != ret) { > > - fepriv->state = FESTATE_IDLE; > > - return; > > - } > > + kthread_stop(fepriv->thread); > > + init_MUTEX (&fepriv->sem); > > the use of the semaphore to synchronise the thread is complex. It will > require extra care to avoid deadlocks. well, it 'works' quite fine for now, but yeah, I thought about completely removing the additional synchronization and 'jsut' go with the kthread one, if that is sufficient ... > > fepriv->state = FESTATE_IDLE; > > > > /* paranoia check in case a signal arrived */ > > - if (fepriv->thread_pid) > > - printk("dvb_frontend_stop: warning: thread PID %d won't exit\n", > > - fepriv->thread_pid); > > + if (fepriv->thread) > > + printk("dvb_frontend_stop: warning: thread %p won't exit\n", > > + fepriv->thread); > > kthread_stop uses a completion already. so the above is real paranoia :) again, I think this will go away soon :) > > } > > > > s32 timeval_usec_diff(struct timeval lasttime, struct timeval curtime) > > @@ -684,10 +662,11 @@ static int dvb_frontend_start(struct dvb > > { > > int ret; > > struct dvb_frontend_private *fepriv = fe->frontend_priv; > > + struct task_struct *fe_thread; > > > > dprintk ("%s\n", __FUNCTION__); > > > > - if (fepriv->thread_pid) { > > + if (fepriv->thread) { > > if (!fepriv->exit) > > return 0; > > else > > @@ -701,18 +680,18 @@ static int dvb_frontend_start(struct dvb > > > > fepriv->state = FESTATE_IDLE; > > fepriv->exit = 0; > > - fepriv->thread_pid = 0; > > + fepriv->thread = NULL; > > mb(); > > > > - ret = kernel_thread (dvb_frontend_thread, fe, 0); > > - > > - if (ret < 0) { > > - printk("dvb_frontend_start: failed to start kernel_thread (%d)\n", ret); > > + fe_thread = kthread_run(dvb_frontend_thread, fe, > > + "kdvb-fe-%i", fe->dvb->num); > > + if (IS_ERR(fe_thread)) { > > + ret = PTR_ERR(fe_thread); > > ret could be local. correct, will fix that up in the next round thanks for the feedback, Herbert > [ ... ] > > _______________________________________________ > Containers mailing list > Containers@lists.osdl.org > https://lists.osdl.org/mailman/listinfo/containers - 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/