From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935381Ab1JEVrT (ORCPT ); Wed, 5 Oct 2011 17:47:19 -0400 Received: from mail-pz0-f42.google.com ([209.85.210.42]:57353 "EHLO mail-pz0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932499Ab1JEVrS (ORCPT ); Wed, 5 Oct 2011 17:47:18 -0400 Date: Wed, 5 Oct 2011 14:47:15 -0700 From: Andrew Morton To: Axel Lin Cc: linux-kernel@vger.kernel.org, Samu Onkalo , Richard Purdie Subject: Re: [PATCH] leds: leds-lp5521: Avoid writing uninitialized value to LP5521_REG_OP_MODE register Message-Id: <20111005144715.5e275a53.akpm@linux-foundation.org> In-Reply-To: <1317806378.2834.6.camel@phoenix> References: <1317806378.2834.6.camel@phoenix> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 05 Oct 2011 17:19:38 +0800 Axel Lin wrote: > If lp5521_read fails, engine_state variable is not initialized. > If lp5521_read fails, we should return error. > This patch fixes below warning. > > CC drivers/leds/leds-lp5521.o > drivers/leds/leds-lp5521.c: In function 'lp5521_set_engine_mode': > drivers/leds/leds-lp5521.c:168: warning: 'engine_state' may be used uninitialized in this function > > Signed-off-by: Axel Lin > --- > drivers/leds/leds-lp5521.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/drivers/leds/leds-lp5521.c b/drivers/leds/leds-lp5521.c > index 9fc122c..89134d9 100644 > --- a/drivers/leds/leds-lp5521.c > +++ b/drivers/leds/leds-lp5521.c > @@ -175,6 +175,8 @@ static int lp5521_set_engine_mode(struct lp5521_engine *engine, u8 mode) > mode = LP5521_CMD_DIRECT; > > ret = lp5521_read(client, LP5521_REG_OP_MODE, &engine_state); > + if (ret < 0) > + return ret; > > /* set mode only for this engine */ > engine_state &= ~(engine->engine_mask); OK. And the later "ret |=" whcih was previously a bug is now just unneeded. --- a/drivers/leds/leds-lp5521.c~leds-leds-lp5521-avoid-writing-uninitialized-value-to-lp5521_reg_op_mode-register-fix +++ a/drivers/leds/leds-lp5521.c @@ -182,9 +182,7 @@ static int lp5521_set_engine_mode(struct engine_state &= ~(engine->engine_mask); mode &= engine->engine_mask; engine_state |= mode; - ret |= lp5521_write(client, LP5521_REG_OP_MODE, engine_state); - - return ret; + return lp5521_write(client, LP5521_REG_OP_MODE, engine_state); } static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern) _