From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753934AbdK0Rnp (ORCPT ); Mon, 27 Nov 2017 12:43:45 -0500 Received: from foss.arm.com ([217.140.101.70]:42256 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752896AbdK0Rno (ORCPT ); Mon, 27 Nov 2017 12:43:44 -0500 Date: Mon, 27 Nov 2017 17:44:11 +0000 From: Lorenzo Pieralisi To: Niklas Cassel Cc: Kishon Vijay Abraham I , Bjorn Helgaas , Niklas Cassel , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 3/3] PCI: endpoint: Fix find_first_zero_bit() usage Message-ID: <20171127174411.GA4123@red-moon> References: <20171127154955.22214-1-niklas.cassel@axis.com> <20171127154955.22214-4-niklas.cassel@axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171127154955.22214-4-niklas.cassel@axis.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 27, 2017 at 04:49:55PM +0100, Niklas Cassel wrote: > find_first_zero_bit()'s parameter 'size' is defined in bits, > not in bytes. > > Calling find_first_zero_bit() with the wrong size unit > will lead to insidious bugs. > > Fix this by calling find_first_zero_bit() with size BITS_PER_LONG, > rather than sizeof(). > > Also add proper error handling for find_first_zero_bit(), since this > was missing. "Fix this by calling find_first_zero_bit() with size BITS_PER_LONG, rather than sizeof() and add missing find_first_zero_bit() return handling" > Fixes: d74679911610 ("PCI: endpoint: Introduce configfs entry for configuring EP functions") > Signed-off-by: Niklas Cassel > --- > drivers/pci/endpoint/pci-ep-cfs.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c > index e1f5adc9e113..0a22a7976580 100644 > --- a/drivers/pci/endpoint/pci-ep-cfs.c > +++ b/drivers/pci/endpoint/pci-ep-cfs.c > @@ -109,7 +109,12 @@ static int pci_epc_epf_link(struct config_item *epc_item, > return ret; > > func_no = find_first_zero_bit(&epc_group->function_num_map, > - sizeof(epc_group->function_num_map)); > + BITS_PER_LONG); > + if (func_no >= BITS_PER_LONG) { > + ret = -EINVAL; > + dev_err(&epc->dev, "failed to link endpoint function device\n"); I would not log the error for the time being or make it more explicit: dev_error(&epc->dev, "unsupported number of functions, failed to link endpoint function device\n"); Side note: we _do_ know the max number of functions the epc supports (epc->max_functions) when this code is called so we do know the bitmap size - we can rework this code path based on that (@kishon, thoughts ?). Other than that: Acked-by: Lorenzo Pieralisi > + goto err_func_no; > + } > set_bit(func_no, &epc_group->function_num_map); > epf->func_no = func_no; > > @@ -121,6 +126,7 @@ static int pci_epc_epf_link(struct config_item *epc_item, > > err_epf_bind: > clear_bit(func_no, &epc_group->function_num_map); > +err_func_no: > pci_epc_remove_epf(epc, epf); > > return ret; > -- > 2.14.2 >