From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Date: Wed, 04 Jun 2014 11:07:34 +0000 Subject: Re: [PATCH 0/10] use safer test on the result of find_first_zero_bit Message-Id: List-Id: References: <1401872880-23685-1-git-send-email-Julia.Lawall@lip6.fr> <063D6719AE5E284EB5DD2968C1650D6D1725705F@AcuExch.aculab.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Julia Lawall Cc: David Laight , linux-rdma , "kernel-janitors-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linux Fbdev development list , Linux-sh list , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "ath10k-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , linux-wireless , "netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , driverdevel , "iss_storagedev-VXdhtT5mjnY@public.gmane.org" , scsi , linux-s390 , "adi-buildroot-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" , Arnd Bergmann Hi Julia, On Wed, Jun 4, 2014 at 1:00 PM, Julia Lawall wrote: > OK, thanks. I was only looking at the C code. > > But the C code contains a loop that is followed by: > > if (!size) > return result; > tmp = *p; > > found_first: > tmp |= ~0UL << size; > if (tmp = ~0UL) /* Are any bits zero? */ > return result + size; /* Nope. */ > > In the first return, it would seem that result = size. Could the second > one be changed to just return size? It should not hurt performance. "size" may have been changed between function entry and this line. So you have to store it in a temporary. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds