From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roel Kluin Subject: Re: [PATCH] spi: limit reaches -1, tested 0 Date: Sun, 08 Feb 2009 18:46:47 +0100 Message-ID: <498F1A87.8060403@gmail.com> References: <498EE9C0.3010601@gmail.com> <200902080755.26241.david-b@pacbell.net> <200902080828.49036.david-b@pacbell.net> <498F0D64.4040909@gmail.com> <498F1979.1030104@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: David Brownell , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Andrew Morton , lkml To: Mariusz Ceier Return-path: In-Reply-To: <498F1979.1030104-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org Mariusz Ceier wrote: > Roel Kluin writes in first post: >> - while ((read(drv_data) == 0) && limit--); >> + while ((read(drv_data) == 0) && --limit); > > Roel Kluin writes in last post: >> - while ((read(drv_data) == 0) && limit--); >> + while ((read(drv_data) == 0) && limit--) >> + cpu_relax(); > > so should there be postfix or prefix decrement ? :) Thanks for spotting, I took the liberty to add David Brownell's Acked-by in this case. ----------------------->8------------------8<--------------------------- With a postfix decrement limit will reach -1 rather than 0, so the warning will not be issued. Signed-off-by: Roel Kluin Acked-by: David Brownell --- diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c index 269a55e..b143e8c 100644 --- a/drivers/spi/spi_imx.c +++ b/drivers/spi/spi_imx.c @@ -779,7 +779,8 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data) /* Read trailing bytes */ limit = loops_per_jiffy << 1; - while ((read(drv_data) == 0) && limit--); + while ((read(drv_data) == 0) && --limit) + cpu_relax(); if (limit == 0) dev_err(&drv_data->pdev->dev, ------------------------------------------------------------------------------ Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753545AbZBHRq6 (ORCPT ); Sun, 8 Feb 2009 12:46:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752264AbZBHRqu (ORCPT ); Sun, 8 Feb 2009 12:46:50 -0500 Received: from ey-out-2122.google.com ([74.125.78.26]:24208 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752662AbZBHRqt (ORCPT ); Sun, 8 Feb 2009 12:46:49 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=Olja7cGuazBrxTft1OKulMqMl++9QDN3NUeGwbYiyitCfV3v+lycveFLXNUDjYjSDP SztAGHkI2HOFF0ZfDACZcFaq+v4IkuoI9E8z8LrrbZt3Monoag++DdEDh72uVDIQ+k7k mkLblkfy6e0Po5364ITC+/eZGhFW367P4Ds3s= Message-ID: <498F1A87.8060403@gmail.com> Date: Sun, 08 Feb 2009 18:46:47 +0100 From: Roel Kluin User-Agent: Thunderbird 2.0.0.18 (X11/20081105) MIME-Version: 1.0 To: Mariusz Ceier CC: David Brownell , spi-devel-general@lists.sourceforge.net, lkml , Andrew Morton Subject: Re: [PATCH] spi: limit reaches -1, tested 0 References: <498EE9C0.3010601@gmail.com> <200902080755.26241.david-b@pacbell.net> <200902080828.49036.david-b@pacbell.net> <498F0D64.4040909@gmail.com> <498F1979.1030104@gmail.com> In-Reply-To: <498F1979.1030104@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mariusz Ceier wrote: > Roel Kluin writes in first post: >> - while ((read(drv_data) == 0) && limit--); >> + while ((read(drv_data) == 0) && --limit); > > Roel Kluin writes in last post: >> - while ((read(drv_data) == 0) && limit--); >> + while ((read(drv_data) == 0) && limit--) >> + cpu_relax(); > > so should there be postfix or prefix decrement ? :) Thanks for spotting, I took the liberty to add David Brownell's Acked-by in this case. ----------------------->8------------------8<--------------------------- With a postfix decrement limit will reach -1 rather than 0, so the warning will not be issued. Signed-off-by: Roel Kluin Acked-by: David Brownell --- diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c index 269a55e..b143e8c 100644 --- a/drivers/spi/spi_imx.c +++ b/drivers/spi/spi_imx.c @@ -779,7 +779,8 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data) /* Read trailing bytes */ limit = loops_per_jiffy << 1; - while ((read(drv_data) == 0) && limit--); + while ((read(drv_data) == 0) && --limit) + cpu_relax(); if (limit == 0) dev_err(&drv_data->pdev->dev,