Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752565Ab2JJHTJ (ORCPT ); Wed, 10 Oct 2012 03:19:09 -0400 Received: from mail-ea0-f174.google.com ([209.85.215.174]:55549 "EHLO mail-ea0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751526Ab2JJHS7 convert rfc822-to-8bit (ORCPT ); Wed, 10 Oct 2012 03:18:59 -0400 From: Jack Morgenstein Organization: Mellanox To: Paul Bolle Subject: Re: [PATCH] IB/lmx4: silence GCC warning Date: Wed, 10 Oct 2012 09:23:43 +0200 User-Agent: KMail/1.9.1 Cc: Roland Dreier , Sean Hefty , Hal Rosenstock , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org References: <1348836538.3626.21.camel@x61.thuisdomein> In-Reply-To: <1348836538.3626.21.camel@x61.thuisdomein> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <201210100923.43927.jackm@dev.mellanox.co.il> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2203 Lines: 54 You could use: u16 uninitialized_var(vlan); instead. Although this in the special QP data flow, I still prefer to avoid adding extra code (even setting initial values at procedure entry). The line above will also do the job. "uninitialized_var" is used elsewhere in the driver. See, for example, mlx4_ib_post_send() in the same file (qp.c). -Jack On Friday 28 September 2012 14:48, Paul Bolle wrote: > Building qp.o (part of the "Mellanox ConnectX HCA support" driver) > triggers this GCC warning: > drivers/infiniband/hw/mlx4/qp.c: In function ‘mlx4_ib_post_send’: > drivers/infiniband/hw/mlx4/qp.c:1828:30: warning: ‘vlan’ may be used uninitialized in this function [-Wmaybe-uninitialized] > drivers/infiniband/hw/mlx4/qp.c:1718:6: note: ‘vlan’ was declared here > > Looking at the code it is clear 'vlan' is only set and used if 'is_eth' > is non-zero. But there's no harm in initializing 'vlan' to 0 (which > matches ib_get_cached_gid()'s default return) to silence GCC. > > Signed-off-by: Paul Bolle > --- > 0) I noticed this warning while building v3.6-rc7 on current Fedora 17, > using Fedora's default config. > > 1) Compile tested only. I tested against v3.6-rc7, with commit > a41262bb5721f2b708ee8b23f67be2f2e16a2fab ("IB/mlx4: SR-IOV IB context > objects and proxy/tunnel SQP") from linux-next cherry-picked, to take > into account a trivial context change in linux-next. > > drivers/infiniband/hw/mlx4/qp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c > index a862251..71fdda6 100644 > --- a/drivers/infiniband/hw/mlx4/qp.c > +++ b/drivers/infiniband/hw/mlx4/qp.c > @@ -1715,7 +1715,7 @@ static int build_mlx_header(struct mlx4_ib_sqp *sqp, struct ib_send_wr *wr, > int is_eth; > int is_vlan = 0; > int is_grh; > - u16 vlan; > + u16 vlan = 0; > int err = 0; > > send_size = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/