From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36464) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fmxAq-00032v-2T for qemu-devel@nongnu.org; Tue, 07 Aug 2018 04:17:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fmxAm-0003Pi-2i for qemu-devel@nongnu.org; Tue, 07 Aug 2018 04:17:00 -0400 Received: from mga03.intel.com ([134.134.136.65]:23095) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fmxAl-0003Oo-Pj for qemu-devel@nongnu.org; Tue, 07 Aug 2018 04:16:56 -0400 Message-ID: <5B69567B.8050309@intel.com> Date: Tue, 07 Aug 2018 16:21:15 +0800 From: Wei Wang MIME-Version: 1.0 References: <1533031278-5615-1-git-send-email-wei.w.wang@intel.com> <20180807073905.GA7265@xz-mi> In-Reply-To: <20180807073905.GA7265@xz-mi> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] bitmap: fix BITMAP_LAST_WORD_MASK List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, quintela@redhat.com, mst@redhat.com On 08/07/2018 03:39 PM, Peter Xu wrote: > On Tue, Jul 31, 2018 at 06:01:18PM +0800, Wei Wang wrote: >> When "nbits = 0", which means no bits to mask, this macro is expected to >> return 0, instead of 0xffffffff. This patch changes the macro to return >> 0 when there is no bit needs to be masked. >> >> Signed-off-by: Wei Wang >> CC: Juan Quintela >> CC: Dr. David Alan Gilbert >> CC: Peter Xu > Reviewed-by: Peter Xu > > Is there any existing path that can trigger this nbits==0? Not sure about other bitmap APIs which call this macro. But it happens in the patches we are working on, which use bitmap_count_one. It would be good to have the macro itself handle this corner case, so that callers won't need to worry about that. Best, Wei