From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758974Ab1EMAAF (ORCPT ); Thu, 12 May 2011 20:00:05 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:30198 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758906Ab1EMAAD (ORCPT ); Thu, 12 May 2011 20:00:03 -0400 Message-ID: <4DCC7441.3070408@kernel.org> Date: Thu, 12 May 2011 16:58:57 -0700 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110414 SUSE/3.1.10 Thunderbird/3.1.10 MIME-Version: 1.0 To: Jesse Barnes CC: Jeff Kirsher , Jesse Brandeburg , Bruce Allan , Carolyn Wyborny , Don Skidmore , Greg Rose , PJ Waskiewicz , Alex Duyck , John Ronciak , "Rafael J. Wysocki" , Kenji Kaneshige , Matthew Garrett , Naga Chumbalkar , e1000-devel@lists.sourceforge.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Andrew Morton Subject: Re: [PATCH] pci, e1000e: Add and use __pci_disable_link_state References: <4DC6E6E8.9040306@kernel.org> <20110509143536.08bd0297@jbarnes-desktop> <4DCAF039.4030207@kernel.org> <20110512163210.132a2954@jbarnes-desktop> In-Reply-To: <20110512163210.132a2954@jbarnes-desktop> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: rtcsinet21.oracle.com [66.248.204.29] X-CT-RefId: str=0001.0A090202.4DCC744D.00BA,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/12/2011 04:32 PM, Jesse Barnes wrote: > On Wed, 11 May 2011 13:23:21 -0700 > Yinghai Lu wrote: > >> On 05/09/2011 02:35 PM, Jesse Barnes wrote: >>> On Sun, 08 May 2011 11:54:32 -0700 >>> Yinghai Lu wrote: >>> >>>> >>>> Need to use it in _e1000e_disable_aspm. >>>> when aer happens, >>>> pci_walk_bus already have down_read(&pci_bus_sem)... >>>> then report_slot_reset >>>> ==> e1000_io_slot_reset >>>> ==> e1000e_disable_aspm >>>> ==> pci_disable_link_state... >>>> >>>> We can not use pci_disable_link_state, and it will try to hold pci_bus_sem again. >>>> >>>> Try to have __pci_disable_link_state that will not need to hold pci_bus_sem. >>> >>> What about the other callers of e1000e_disable_aspm? Do they already >>> have the lock held or is it just reset that needs the already locked >>> version? >> >> yes. >> >> there is another version when aspm is not defined. and it does not use any lock. >> >> #ifdef CONFIG_PCIEASPM >> static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state) >> { >> pci_disable_link_state(pdev, state); >> } >> #else >> static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state) >> { >> int pos; >> u16 reg16; >> >> /* >> * Both device and parent should have the same ASPM setting. >> * Disable ASPM in downstream component first and then upstream. >> */ >> pos = pci_pcie_cap(pdev); >> pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, ®16); >> reg16 &= ~state; >> pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16); >> >> if (!pdev->bus->self) >> return; >> >> pos = pci_pcie_cap(pdev->bus->self); >> pci_read_config_word(pdev->bus->self, pos + PCI_EXP_LNKCTL, ®16); >> reg16 &= ~state; >> pci_write_config_word(pdev->bus->self, pos + PCI_EXP_LNKCTL, reg16); >> } >> #endif > > No, I mean __e1000e_disable_aspm is called from several spots: > > *** drivers/net/e1000e/82571.c: > e1000_get_variants_82571[435] e1000e_disable_aspm(adapter->pdev, PCIE_LINK_STATE_L0S); > > *** drivers/net/e1000e/netdev.c: > e1000_change_mtu[5027] e1000e_disable_aspm(adapter->pdev, PCIE_LINK_STATE_L1); > __e1000_resume[5402] e1000e_disable_aspm(pdev, PCIE_LINK_STATE_L1); > e1000_io_slot_reset[5650] e1000e_disable_aspm(pdev, PCIE_LINK_STATE_L1); > e1000_probe[5797] e1000e_disable_aspm(pdev, PCIE_LINK_STATE_L1); > > Are all of them safe for the unlocked version of ASPM disable? yes, there are two version __e1000e_disable_aspm(), one is when aspm support is compiled in, and another one is not. the one without aspm compiled does not use pci_bus_sem in it self... So I assume another path should not use pci_bus_sem in the function itself. Yinghai