From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:43652) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h1UxC-0006Qp-3F for qemu-devel@nongnu.org; Wed, 06 Mar 2019 06:43:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h1UxB-0005CG-6m for qemu-devel@nongnu.org; Wed, 06 Mar 2019 06:43:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39846) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h1UxB-00059p-0Z for qemu-devel@nongnu.org; Wed, 06 Mar 2019 06:43:17 -0500 From: "Dr. David Alan Gilbert (git)" Date: Wed, 6 Mar 2019 11:42:18 +0000 Message-Id: <20190306114227.9125-14-dgilbert@redhat.com> In-Reply-To: <20190306114227.9125-1-dgilbert@redhat.com> References: <20190306114227.9125-1-dgilbert@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 13/22] bitmap: fix bitmap_count_one List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, quintela@redhat.com, peterx@redhat.com, marcel.apfelbaum@gmail.com, wei.w.wang@intel.com, yury-kotov@yandex-team.ru, chen.zhang@intel.com Cc: eblake@redhat.com, armbru@redhat.com From: Wei Wang BITMAP_LAST_WORD_MASK(nbits) returns 0xffffffff when "nbits=3D0", which makes bitmap_count_one fail to handle the "nbits=3D0" case. It appears to= be preferred to remain BITMAP_LAST_WORD_MASK identical to the kernel implementation that it is ported from. So this patch fixes bitmap_count_one to handle the nbits=3D0 case. Inital Discussion Link: https://www.mail-archive.com/qemu-devel@nongnu.org/msg554316.html Signed-off-by: Wei Wang CC: Juan Quintela CC: Dr. David Alan Gilbert CC: Peter Xu Message-Id: <1544516693-5395-2-git-send-email-wei.w.wang@intel.com> Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Dr. David Alan Gilbert --- include/qemu/bitmap.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h index 509eeddece..679f1bdce4 100644 --- a/include/qemu/bitmap.h +++ b/include/qemu/bitmap.h @@ -221,6 +221,10 @@ static inline int bitmap_intersects(const unsigned l= ong *src1, =20 static inline long bitmap_count_one(const unsigned long *bitmap, long nb= its) { + if (unlikely(!nbits)) { + return 0; + } + if (small_nbits(nbits)) { return ctpopl(*bitmap & BITMAP_LAST_WORD_MASK(nbits)); } else { --=20 2.20.1