From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37836) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fn0w0-0007ZG-9F for qemu-devel@nongnu.org; Tue, 07 Aug 2018 08:17:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fn0vw-0002ID-UT for qemu-devel@nongnu.org; Tue, 07 Aug 2018 08:17:56 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56968 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fn0vw-0002I3-Of for qemu-devel@nongnu.org; Tue, 07 Aug 2018 08:17:52 -0400 Date: Tue, 7 Aug 2018 20:17:46 +0800 From: Peter Xu Message-ID: <20180807121746.GB7265@xz-mi> References: <1533031278-5615-1-git-send-email-wei.w.wang@intel.com> <20180807073905.GA7265@xz-mi> <5B69567B.8050309@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5B69567B.8050309@intel.com> 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: Wei Wang Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, quintela@redhat.com, mst@redhat.com On Tue, Aug 07, 2018 at 04:21:15PM +0800, Wei Wang wrote: > 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. Yeah that makes sense. Asked since that would matter on whether it's 3.0 material, then it's possibly not. Regards, -- Peter Xu