Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752569AbYJ0HPK (ORCPT ); Mon, 27 Oct 2008 03:15:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751772AbYJ0HO5 (ORCPT ); Mon, 27 Oct 2008 03:14:57 -0400 Received: from mga09.intel.com ([134.134.136.24]:11577 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751649AbYJ0HO5 (ORCPT ); Mon, 27 Oct 2008 03:14:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.33,491,1220252400"; d="scan'208";a="352591629" Message-ID: <49056A2F.6030206@intel.com> Date: Mon, 27 Oct 2008 15:13:51 +0800 From: "Zhao, Yu" User-Agent: Thunderbird 2.0.0.17 (Windows/20080914) MIME-Version: 1.0 To: Matthew Wilcox CC: Yu Zhao , Jesse Barnes , "linux-pci@vger.kernel.org" , "greg@kroah.com" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "stable@kernel.org" , Rakib Mullick Subject: Re: [PATCH] pci: Fixing drivers/pci/search.c compilation warning. References: <20080928163211.GR27204@parisc-linux.org> <20081021011308.GA3889@parisc-linux.org> <490467CD.3000402@uniscape.net> <20081026183412.GX26094@parisc-linux.org> <49053313.9080706@intel.com> <20081027070745.GY26094@parisc-linux.org> In-Reply-To: <20081027070745.GY26094@parisc-linux.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1377 Lines: 35 Matthew Wilcox wrote: > On Mon, Oct 27, 2008 at 11:18:43AM +0800, Zhao, Yu wrote: >> Matthew Wilcox wrote: >>> Yes, that's why pci_find_device() is deprecated. But it doesn't also >>> need to be buggy ;-) >> How about pci_get_bus_and_slot()? People would meet the problem with it >> anyway. > > What problem with it? It's documented to return the device with an > increased refcount, and the implementation appears to do exactly that: > > struct pci_dev * pci_get_bus_and_slot(unsigned int bus, unsigned int devfn) > { > struct pci_dev *dev = NULL; > > while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) { > if (pci_domain_nr(dev->bus) == 0 && > (dev->bus->number == bus && dev->devfn == devfn)) > return dev; > } > return NULL; > } > > Are you saying some users of it neglect to decrement the refcount before > disposing of the device? > The 'dev' returned by pci_get_device() may be destroyed by PCI hotplug. I suppose that passing this 'dev' to pci_get_device() in the next loop would crash the system, right? -- 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/