Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754809AbZAITu0 (ORCPT ); Fri, 9 Jan 2009 14:50:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752315AbZAITuL (ORCPT ); Fri, 9 Jan 2009 14:50:11 -0500 Received: from einhorn.in-berlin.de ([192.109.42.8]:42042 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752058AbZAITuJ (ORCPT ); Fri, 9 Jan 2009 14:50:09 -0500 X-Envelope-From: stefanr@s5r6.in-berlin.de Date: Fri, 9 Jan 2009 20:49:37 +0100 (CET) From: Stefan Richter Subject: [PATCH post 2.6.28] firewire: core: fix sleep in atomic context due to driver core change To: linux1394-devel@lists.sourceforge.net cc: Kay Sievers , linux-kernel@vger.kernel.org, Jay Fenlason , Greg Kroah-Hartman In-Reply-To: <496798FE.8030900@s5r6.in-berlin.de> Message-ID: References: <496798FE.8030900@s5r6.in-berlin.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=us-ascii Content-Disposition: INLINE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4823 Lines: 137 Due to commit 2831fe6f9cc4e16c103504ee09a47a084297c0f3, "driver core: create a private portion of struct device", device_initialize() can no longer be called from atomic contexts. We now defer it until after config ROM probing. This requires changes to the bus manager code because this may use a device before it was probed. Reported-by: Jay Fenlason Signed-off-by: Stefan Richter --- This still needs a lot of testing since I may have easily missed something. Even if it works, it complicates firewire-core's lifetime rules. Better would be to fix driver core to not sleep in device_initialize (and besides, never fail in void device_initialize). drivers/firewire/fw-card.c | 13 +++++++------ drivers/firewire/fw-device.c | 23 +++++++++++++---------- 2 files changed, 20 insertions(+), 16 deletions(-) Index: linux/drivers/firewire/fw-device.c =================================================================== --- linux.orig/drivers/firewire/fw-device.c +++ linux/drivers/firewire/fw-device.c @@ -160,7 +160,8 @@ static void fw_device_release(struct dev /* * Take the card lock so we don't set this to NULL while a - * FW_NODE_UPDATED callback is being handled. + * FW_NODE_UPDATED callback is being handled or while the + * bus manager work looks at this node. */ spin_lock_irqsave(&card->lock, flags); device->node->data = NULL; @@ -693,12 +694,13 @@ static void fw_device_init(struct work_s return; } - err = -ENOMEM; + device_initialize(&device->device); fw_device_get(device); down_write(&fw_device_rwsem); - if (idr_pre_get(&fw_device_idr, GFP_KERNEL)) - err = idr_get_new(&fw_device_idr, device, &minor); + err = idr_pre_get(&fw_device_idr, GFP_KERNEL) ? + idr_get_new(&fw_device_idr, device, &minor) : + -ENOMEM; up_write(&fw_device_rwsem); if (err < 0) @@ -909,13 +911,14 @@ void fw_node_event(struct fw_card *card, /* * Do minimal intialization of the device here, the - * rest will happen in fw_device_init(). We need the - * card and node so we can read the config rom and we - * need to do device_initialize() now so - * device_for_each_child() in FW_NODE_UPDATED is - * doesn't freak out. + * rest will happen in fw_device_init(). + * + * Attention: A lot of things, even fw_device_get(), + * cannot be done before fw_device_init() finished! + * You can basically just check device->state and + * schedule work until then, but only while holding + * card->lock. */ - device_initialize(&device->device); atomic_set(&device->state, FW_DEVICE_INITIALIZING); device->card = fw_card_get(card); device->node = fw_node_get(node); Index: linux/drivers/firewire/fw-card.c =================================================================== --- linux.orig/drivers/firewire/fw-card.c +++ linux/drivers/firewire/fw-card.c @@ -203,6 +203,8 @@ static void fw_card_bm_work(struct work_ unsigned long flags; int root_id, new_root_id, irm_id, gap_count, generation, grace, rcode; bool do_reset = false; + bool root_device_is_running; + bool root_device_is_cmc; __be32 lock_data[2]; spin_lock_irqsave(&card->lock, flags); @@ -218,8 +220,9 @@ static void fw_card_bm_work(struct work_ generation = card->generation; root_device = root_node->data; - if (root_device) - fw_device_get(root_device); + root_device_is_running = root_device && + atomic_read(&root_device->state) == FW_DEVICE_RUNNING; + root_device_is_cmc = root_device && root_device->cmc; root_id = root_node->node_id; grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 10)); @@ -302,14 +305,14 @@ static void fw_card_bm_work(struct work_ * config rom. In either case, pick another root. */ new_root_id = local_node->node_id; - } else if (atomic_read(&root_device->state) != FW_DEVICE_RUNNING) { + } else if (!root_device_is_running) { /* * If we haven't probed this device yet, bail out now * and let's try again once that's done. */ spin_unlock_irqrestore(&card->lock, flags); goto out; - } else if (root_device->cmc) { + } else if (root_device_is_cmc) { /* * FIXME: I suppose we should set the cmstr bit in the * STATE_CLEAR register of this node, as described in @@ -356,8 +359,6 @@ static void fw_card_bm_work(struct work_ fw_core_initiate_bus_reset(card, 1); } out: - if (root_device) - fw_device_put(root_device); fw_node_put(root_node); fw_node_put(local_node); out_put_card: -- Stefan Richter -=====-==--= ---= -=--= http://arcgraph.de/sr/ -- 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/