From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH] ide_dma_speed() fixes Date: Mon, 15 May 2006 17:44:30 +0400 Message-ID: <446885BE.4090404@ru.mvista.com> References: <4463F4C8.9080608@ru.mvista.com> <20060514050548.5399e3f4.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtsoft2.corbina.net ([85.21.88.2]:19373 "HELO mail.dev.rtsoft.ru") by vger.kernel.org with SMTP id S964909AbWEONpf (ORCPT ); Mon, 15 May 2006 09:45:35 -0400 In-Reply-To: <20060514050548.5399e3f4.akpm@osdl.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Andrew Morton Cc: bzolnier@gmail.com, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hello. Andrew Morton wrote: >> ide_dma_speed() fails to actually honor the IDE drivers' mode support >> masks) because of the bogus checks -- thus, selecting the DMA transfer mode >> that the driver explicitly refuses to support is possible. Additionally, there >> is no check for validity of the UltraDMA mode data in the drive ID, and the >> function is misdocumented. > drivers/ide/ide-lib.c: In function `ide_dma_speed': > drivers/ide/ide-lib.c:86: warning: `ultra_mask' might be used uninitialized in this function > Looks like a real bug to me - it depends up on the values of `mode' and > id->field_value. > Anyway, I'll drop it, please review and fix. I assume that warning was > occurring for you as well - please spend more time over these things. > Especially when working on IDE, where bugs are slow to show themselves and > have particularly bad consequences. That's what gcc thinks. The code is 100% correct -- it will never reach the switch statement with mode > 0 (in which case ultra_mask isn't used) and ultra_mask unitialized. I may add an explicit initializer in the declaration if you like... MBR, Sergei