From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julia Lawall Subject: RE: [PATCH 0/10] use safer test on the result of find_first_zero_bit Date: Wed, 4 Jun 2014 11:52:32 +0200 (CEST) Message-ID: References: <1401872880-23685-1-git-send-email-Julia.Lawall@lip6.fr> <063D6719AE5E284EB5DD2968C1650D6D1725705F@AcuExch.aculab.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: 'Julia Lawall' , Geert Uytterhoeven , linux-rdma , "kernel-janitors@vger.kernel.org" , Linux Fbdev development list , Linux-sh list , "linux-kernel@vger.kernel.org" , "ath10k@lists.infradead.org" , linux-wireless , "netdev@vger.kernel.org" , driverdevel , "iss_storagedev@hp.com" , scsi , linux-s390 , "adi-buildroot-devel@lists.sourceforge.net" To: David Laight Return-path: In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1725705F@AcuExch.aculab.com> Sender: kernel-janitors-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Wed, 4 Jun 2014, David Laight wrote: > From: Julia Lawall > > On Wed, 4 Jun 2014, Geert Uytterhoeven wrote: > > > > > Hi Julia, > > > > > > On Wed, Jun 4, 2014 at 11:07 AM, Julia Lawall wrote: > > > > Find_first_zero_bit considers BITS_PER_LONG bits at a time, and thus may > > > > return a larger number than the maximum position argument if that position > > > > is not a multiple of BITS_PER_LONG. > > > > > > Shouldn't this be fixed in find_first_zero_bit() instead? > > > > OK, I could do that as well. Most of the callers currently test with >=. > > Should they be left as is, or changed to use ==? > > Do we want to add an extra test to find_first_zero_bit() and effectively > slow down all the calls - especially those where the length is a > multiple of 8 (probably the most common). Currently, most of the calls test with >=, and most of the others seem to need to (either the size value did not look like a multiple of anything in particular, or it was eg read from a device). Note that it is BITS_PER_LONG, so it seems like it is typically 32 or 64, not 8. > Maybe the documented return code should be changed to allow for the > existing behaviour. Sorry, I'm not sure to understand what you suggest here. thanks, julia