Return-path: Received: from rv-out-0910.google.com ([209.85.198.190]:12408 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752951AbYANIfQ (ORCPT ); Mon, 14 Jan 2008 03:35:16 -0500 Received: by rv-out-0910.google.com with SMTP id k20so1702280rvb.1 for ; Mon, 14 Jan 2008 00:35:15 -0800 (PST) Message-ID: <478B1EBF.8030701@gmail.com> (sfid-20080114_083521_933131_4C79FEE3) Date: Mon, 14 Jan 2008 17:35:11 +0900 From: Joonwoo Park MIME-Version: 1.0 To: "Zhu, Yi" , netdev@vger.kernel.org CC: "Chatre, Reinette" , linux-wireless@vger.kernel.org, ipw3945-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [ipw3945-devel] [PATCH 2/5] iwlwifi: iwl3945 synchronize interruptand tasklet for down iwlwifi References: <11998765481610-git-send-email-joonwpark81@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: Joonwoo Park wrote: > 2008/1/11, Chatre, Reinette : >> On Thursday, January 10, 2008 5:25 PM, Joonwoo Park wrote: > >> What modification are you considering? > > Roughly, I'm considering make synchronize_irq() be moved into > iwl_disable_interrupts() and fix iwl_irq_tasket not to call > iwl_disable_interrupts with irq disabled. > For now iwl_irq_tasklet calls iwl_disable_interrupts() with local irq disabled. > like this: > > static void iwl_irq_tasklet(struct iwl_priv *priv) > { > ... > spin_lock_irqsave(&priv->lock, flags); > > ... > /* Now service all interrupt bits discovered above. */ > if (inta & CSR_INT_BIT_HW_ERR) { > IWL_ERROR("Microcode HW error detected. Restarting.\n"); > > /* Tell the device to stop sending interrupts */ > iwl_disable_interrupts(priv); > ... > spin_unlock_irqrestore(&priv->lock, flags); > return; > } > > After disabling interrupts, it's possible irq & tasklet is pending or running This patch eleminates races for down iwlwifi Since synchronize_irq can introduce iwl_irq_tasklet, tasklet_kill should be called after doing synchronize_irq To avoid races between iwl_synchronize_irq and iwl_irq_tasklet STATUS_INT_ENABLED flag is needed. Signed-off-by: Joonwoo Park --- drivers/net/wireless/iwlwifi/iwl3945-base.c | 33 ++++++++++++++++++++++----- 1 files changed, 27 insertions(+), 6 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c index 6e20725..f98cd4f 100644 --- a/drivers/net/wireless/iwlwifi/iwl3945-base.c +++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c @@ -4405,6 +4405,14 @@ static void iwl_print_rx_config_cmd(struct iwl_rxon_cmd *rxon) } #endif +static void iwl_synchronize_interrupts(struct iwl_priv *priv) +{ + synchronize_irq(priv->pci_dev->irq); + /* synchornize_irq introduces irq_tasklet, + * tasklet_kill should be called after doing synchronize_irq */ + tasklet_kill(&priv->irq_tasklet); +} + static void iwl_enable_interrupts(struct iwl_priv *priv) { IWL_DEBUG_ISR("Enabling interrupts\n"); @@ -4413,7 +4421,7 @@ static void iwl_enable_interrupts(struct iwl_priv *priv) iwl_flush32(priv, CSR_INT_MASK); } -static inline void iwl_disable_interrupts(struct iwl_priv *priv) +static inline void __iwl_disable_interrupts(struct iwl_priv *priv) { clear_bit(STATUS_INT_ENABLED, &priv->status); @@ -4427,6 +4435,13 @@ static inline void iwl_disable_interrupts(struct iwl_priv *priv) iwl_flush32(priv, CSR_INT); iwl_write32(priv, CSR_FH_INT_STATUS, 0xffffffff); iwl_flush32(priv, CSR_FH_INT_STATUS); +} + +static inline void iwl_disable_interrupts(struct iwl_priv *priv) +{ + __iwl_disable_interrupts(priv); + + iwl_synchronize_interrupts(priv); IWL_DEBUG_ISR("Disabled interrupts\n"); } @@ -4708,7 +4723,8 @@ static void iwl_irq_tasklet(struct iwl_priv *priv) IWL_ERROR("Microcode HW error detected. Restarting.\n"); /* Tell the device to stop sending interrupts */ - iwl_disable_interrupts(priv); + __iwl_disable_interrupts(priv); + IWL_DEBUG_ISR("Disabled interrupts\n"); iwl_irq_handle_error(priv); @@ -4814,8 +4830,11 @@ static void iwl_irq_tasklet(struct iwl_priv *priv) IWL_WARNING(" with FH_INT = 0x%08x\n", inta_fh); } - /* Re-enable all interrupts */ - iwl_enable_interrupts(priv); + /* To avoid race when device goes down, + * it should be discarded to enable interrupts */ + if (test_bit(STATUS_INT_ENABLED, &priv->status)) + /* Re-enable all interrupts */ + iwl_enable_interrupts(priv); #ifdef CONFIG_IWLWIFI_DEBUG if (iwl_debug_level & (IWL_DL_ISR)) { @@ -4876,8 +4895,10 @@ unplugged: return IRQ_HANDLED; none: - /* re-enable interrupts here since we don't have anything to service. */ - iwl_enable_interrupts(priv); + if (test_bit(STATUS_INT_ENABLED, &priv->status)) + /* re-enable interrupts here since we don't have anything + * to service. */ + iwl_enable_interrupts(priv); spin_unlock(&priv->lock); return IRQ_NONE; } --- Thanks, Joonwoo