Return-path: Received: from mga11.intel.com ([192.55.52.93]:56573 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751318AbdH3O5R (ORCPT ); Wed, 30 Aug 2017 10:57:17 -0400 Date: Wed, 30 Aug 2017 17:57:26 +0300 From: David Weinehall To: Luca Coelho Cc: jikos@kernel.org, linux-wireless@vger.kernel.org, luciano.coelho@intel.com, linux-kernel@vger.kernel.org, linuxwifi@intel.com, rui.zhang@intel.com, edubezval@gmail.com, linux-pm@vger.kernel.org, david.weinehall@intel.com, johannes.berg@intel.com, kvalo@codeaurora.org, sara.sharon@intel.com, emmanuel.grumbach@intel.com Subject: Re: [PATCH v2] iwlwifi: pcie: move rx workqueue initialization to iwl_trans_pcie_alloc() Message-ID: <20170830145726.eq7qs4jtdsqa74lu@boom> (sfid-20170830_165732_527318_9BDF78F7) References: <20170822073729.4856-1-luca@coelho.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170822073729.4856-1-luca@coelho.fi> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, Aug 22, 2017 at 10:37:29AM +0300, Luca Coelho wrote: > From: Luca Coelho > > Work queues cannot be allocated when a mutex is held because the mutex > may be in use and that would make it sleep. Doing so generates the > following splat with 4.13+: > > [ 19.513298] ====================================================== > [ 19.513429] WARNING: possible circular locking dependency detected > [ 19.513557] 4.13.0-rc5+ #6 Not tainted > [ 19.513638] ------------------------------------------------------ > [ 19.513767] cpuhp/0/12 is trying to acquire lock: > [ 19.513867] (&tz->lock){+.+.+.}, at: [] thermal_zone_get_temp+0x5b/0xb0 > [ 19.514047] > [ 19.514047] but task is already holding lock: > [ 19.514166] (cpuhp_state){+.+.+.}, at: [] cpuhp_thread_fun+0x3a/0x210 > [ 19.514338] > [ 19.514338] which lock already depends on the new lock. > > This lock dependency already existed with previous kernel versions, > but it was not detected until commit 49dfe2a67797 ("cpuhotplug: Link > lock stacks for hotplug callbacks") was introduced. > > Reported-by: David Weinehall > Reported-by: Jiri Kosina > Signed-off-by: Luca Coelho With this patch I no longer get the lockdep warning, and the driver seems to work just as well as before. Thanks! Tested-by: David Weinehall > --- > In v2: > - updated the commit message to a new version, with a grammar fix > and the actual commit that exposed the problem; > > drivers/net/wireless/intel/iwlwifi/pcie/internal.h | 2 ++ > drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 10 +--------- > drivers/net/wireless/intel/iwlwifi/pcie/trans.c | 9 +++++++++ > 3 files changed, 12 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h > index fa315d84e98e..a1ea9ef97ed9 100644 > --- a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h > +++ b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h > @@ -787,6 +787,8 @@ int iwl_pci_fw_enter_d0i3(struct iwl_trans *trans); > > void iwl_pcie_enable_rx_wake(struct iwl_trans *trans, bool enable); > > +void iwl_pcie_rx_allocator_work(struct work_struct *data); > + > /* common functions that are used by gen2 transport */ > void iwl_pcie_apm_config(struct iwl_trans *trans); > int iwl_pcie_prepare_card_hw(struct iwl_trans *trans); > diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c > index 351c4423125a..942736d3fa75 100644 > --- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c > +++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c > @@ -597,7 +597,7 @@ static void iwl_pcie_rx_allocator_get(struct iwl_trans *trans, > rxq->free_count += RX_CLAIM_REQ_ALLOC; > } > > -static void iwl_pcie_rx_allocator_work(struct work_struct *data) > +void iwl_pcie_rx_allocator_work(struct work_struct *data) > { > struct iwl_rb_allocator *rba_p = > container_of(data, struct iwl_rb_allocator, rx_alloc); > @@ -900,10 +900,6 @@ static int _iwl_pcie_rx_init(struct iwl_trans *trans) > return err; > } > def_rxq = trans_pcie->rxq; > - if (!rba->alloc_wq) > - rba->alloc_wq = alloc_workqueue("rb_allocator", > - WQ_HIGHPRI | WQ_UNBOUND, 1); > - INIT_WORK(&rba->rx_alloc, iwl_pcie_rx_allocator_work); > > spin_lock(&rba->lock); > atomic_set(&rba->req_pending, 0); > @@ -1017,10 +1013,6 @@ void iwl_pcie_rx_free(struct iwl_trans *trans) > } > > cancel_work_sync(&rba->rx_alloc); > - if (rba->alloc_wq) { > - destroy_workqueue(rba->alloc_wq); > - rba->alloc_wq = NULL; > - } > > iwl_pcie_free_rbs_pool(trans); > > diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c > index f95eec52508e..3927bbf04f72 100644 > --- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c > +++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c > @@ -1786,6 +1786,11 @@ void iwl_trans_pcie_free(struct iwl_trans *trans) > iwl_pcie_tx_free(trans); > iwl_pcie_rx_free(trans); > > + if (trans_pcie->rba.alloc_wq) { > + destroy_workqueue(trans_pcie->rba.alloc_wq); > + trans_pcie->rba.alloc_wq = NULL; > + } > + > if (trans_pcie->msix_enabled) { > for (i = 0; i < trans_pcie->alloc_vecs; i++) { > irq_set_affinity_hint( > @@ -3169,6 +3174,10 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev, > trans_pcie->inta_mask = CSR_INI_SET_MASK; > } > > + trans_pcie->rba.alloc_wq = alloc_workqueue("rb_allocator", > + WQ_HIGHPRI | WQ_UNBOUND, 1); > + INIT_WORK(&trans_pcie->rba.rx_alloc, iwl_pcie_rx_allocator_work); > + > #ifdef CONFIG_IWLWIFI_PCIE_RTPM > trans->runtime_pm_mode = IWL_PLAT_PM_MODE_D0I3; > #else > -- > 2.14.1 >