From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out6.electric.net ([192.162.217.192]:62347 "EHLO smtp-out6.electric.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751596AbdK1Jwz (ORCPT ); Tue, 28 Nov 2017 04:52:55 -0500 From: David Laight To: 'Niklas Cassel' , Kishon Vijay Abraham I , Lorenzo Pieralisi , Bjorn Helgaas CC: 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 Date: Tue, 28 Nov 2017 09:53:12 +0000 Message-ID: <227791f09ccd4aa8972ba334fd948f4e@AcuMS.aculab.com> References: <20171127154955.22214-1-niklas.cassel@axis.com> <20171127154955.22214-4-niklas.cassel@axis.com> In-Reply-To: <20171127154955.22214-4-niklas.cassel@axis.com> Content-Type: text/plain; charset="Windows-1252" MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org List-ID: From: Niklas Cassel > Sent: 27 November 2017 15:50 > 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. > > 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); Surely this should be either 8 * sizeof() or you should use ffz() that takes a numeric argument rather than the function designed for arbitrary size bitmaps. David