Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265953AbUA1NeT (ORCPT ); Wed, 28 Jan 2004 08:34:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265956AbUA1NeT (ORCPT ); Wed, 28 Jan 2004 08:34:19 -0500 Received: from phoenix.infradead.org ([213.86.99.234]:2315 "EHLO phoenix.infradead.org") by vger.kernel.org with ESMTP id S265953AbUA1NeC (ORCPT ); Wed, 28 Jan 2004 08:34:02 -0500 Date: Wed, 28 Jan 2004 13:33:58 +0000 From: Christoph Hellwig To: Alistair John Strachan Cc: linux-kernel@vger.kernel.org, =?iso-8859-1?Q?David_Mart=EDnez_Moreno?= , Andrew Morton , linux-mm@kvack.org Subject: Fix sleep_on abuse in XFS, Was: Re: 2.6.2-rc2-mm1 (Breakage?) Message-ID: <20040128133357.A28038@infradead.org> Mail-Followup-To: Christoph Hellwig , Alistair John Strachan , linux-kernel@vger.kernel.org, =?iso-8859-1?Q?David_Mart=EDnez_Moreno?= , Andrew Morton , linux-mm@kvack.org References: <20040127233402.6f5d3497.akpm@osdl.org> <200401281313.03790.ender@debian.org> <200401281225.37234.s0348365@sms.ed.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <200401281225.37234.s0348365@sms.ed.ac.uk>; from s0348365@sms.ed.ac.uk on Wed, Jan 28, 2004 at 12:25:37PM +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3633 Lines: 136 Okay, okay, I give up, here's a patch to remove sleep_on usage from XFS. It's not actually racy but such horrible code deserves to be replaced anyway. Index: fs/xfs/linux-2.6/xfs_buf.c =================================================================== RCS file: /cvs/linux-2.6-xfs/fs/xfs/linux-2.6/xfs_buf.c,v retrieving revision 1.136 diff -u -p -r1.136 xfs_buf.c --- fs/xfs/linux-2.6/xfs_buf.c 27 Jan 2004 18:47:46 -0000 1.136 +++ fs/xfs/linux-2.6/xfs_buf.c 28 Jan 2004 13:09:33 -0000 @@ -80,7 +80,7 @@ */ STATIC kmem_cache_t *pagebuf_cache; -STATIC void pagebuf_daemon_wakeup(int); +STATIC void pagebuf_daemon_wakeup(void); STATIC void pagebuf_delwri_queue(page_buf_t *, int); STATIC struct workqueue_struct *pagebuf_logio_workqueue; STATIC struct workqueue_struct *pagebuf_dataio_workqueue; @@ -510,7 +510,7 @@ _pagebuf_lookup_pages( if (!page) { if (--retry_count > 0) { PB_STATS_INC(pb_page_retries); - pagebuf_daemon_wakeup(1); + pagebuf_daemon_wakeup(); current->state = TASK_UNINTERRUPTIBLE; schedule_timeout(10); goto retry; @@ -1640,7 +1605,6 @@ pagebuf_iomove( * Pagebuf delayed write buffer handling */ -STATIC int pbd_active = 1; STATIC LIST_HEAD(pbd_delwrite_queue); STATIC spinlock_t pbd_delwrite_lock = SPIN_LOCK_UNLOCKED; @@ -1687,21 +1651,19 @@ pagebuf_runall_queues( } /* Defines for pagebuf daemon */ -DECLARE_WAIT_QUEUE_HEAD(pbd_waitq); +STATIC DECLARE_COMPLETION(pagebuf_daemon_done); +STATIC struct task_struct *pagebuf_daemon_task; +STATIC int pagebuf_daemon_active; STATIC int force_flush; STATIC void -pagebuf_daemon_wakeup( - int flag) +pagebuf_daemon_wakeup(void) { - force_flush = flag; - if (waitqueue_active(&pbd_waitq)) { - wake_up_interruptible(&pbd_waitq); - } + force_flush = 1; + barrier(); + wake_up_process(pagebuf_daemon_task); } -typedef void (*timeout_fn)(unsigned long); - STATIC int pagebuf_daemon( void *data) @@ -1709,29 +1671,22 @@ pagebuf_daemon( int count; page_buf_t *pb; struct list_head *curr, *next, tmp; - struct timer_list pb_daemon_timer = - TIMER_INITIALIZER((timeout_fn)pagebuf_daemon_wakeup, 0, 0); /* Set up the thread */ daemonize("pagebufd"); - current->flags |= PF_MEMALLOC; + pagebuf_daemon_task = current; + pagebuf_daemon_active = 1; + barrier(); + INIT_LIST_HEAD(&tmp); do { /* swsusp */ if (current->flags & PF_FREEZE) refrigerator(PF_IOTHREAD); - if (pbd_active == 1) { - mod_timer(&pb_daemon_timer, - jiffies + pb_params.flush_interval.val); - interruptible_sleep_on(&pbd_waitq); - } - - if (pbd_active == 0) { - del_timer_sync(&pb_daemon_timer); - } + schedule_timeout(pb_params.flush_interval.val); spin_lock(&pbd_delwrite_lock); @@ -1775,11 +1730,9 @@ pagebuf_daemon( blk_run_queues(); force_flush = 0; - } while (pbd_active == 1); - - pbd_active = -1; - wake_up_interruptible(&pbd_waitq); + } while (pagebuf_daemon_active); + complete(&pagebuf_daemon_done); return 0; } @@ -1890,9 +1843,10 @@ pagebuf_daemon_start(void) STATIC void pagebuf_daemon_stop(void) { - pbd_active = 0; - wake_up_interruptible(&pbd_waitq); - wait_event_interruptible(pbd_waitq, pbd_active); + pagebuf_daemon_active = 0; + barrier(); + wait_for_completion(&pagebuf_daemon_done); + destroy_workqueue(pagebuf_logio_workqueue); destroy_workqueue(pagebuf_dataio_workqueue); } - 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/