From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39E85C4321D for ; Thu, 16 Aug 2018 06:33:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE412214AB for ; Thu, 16 Aug 2018 06:33:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EE412214AB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388999AbeHPJ3W (ORCPT ); Thu, 16 Aug 2018 05:29:22 -0400 Received: from mail.bootlin.com ([62.4.15.54]:48442 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726335AbeHPJ3W (ORCPT ); Thu, 16 Aug 2018 05:29:22 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 5F896207F3; Thu, 16 Aug 2018 08:33:07 +0200 (CEST) Received: from bbrezillon (unknown [91.160.177.164]) by mail.bootlin.com (Postfix) with ESMTPSA id 11D2F20731; Thu, 16 Aug 2018 08:33:07 +0200 (CEST) Date: Thu, 16 Aug 2018 08:33:07 +0200 From: Boris Brezillon To: Chuanhua Han Cc: dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com, richard@nod.at, cyrille.pitchen@wedev4u.fr, broonie@kernel.org, pp@emlix.com, Zhiqiang.Hou@nxp.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mtd: m25p80: consider max message size in m25p80_read when use the spi_mem_xx() API Message-ID: <20180816083307.684bdb72@bbrezillon> In-Reply-To: <1534314823-14048-1-git-send-email-chuanhua.han@nxp.com> References: <1534314823-14048-1-git-send-email-chuanhua.han@nxp.com> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chuanhua, On Wed, 15 Aug 2018 14:33:43 +0800 Chuanhua Han wrote: > Consider a message size limit when calculating the maximum amount > of data that can be read. > > Signed-off-by: Chuanhua Han > --- > drivers/mtd/devices/m25p80.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c > index e84563d..87efa56 100644 > --- a/drivers/mtd/devices/m25p80.c > +++ b/drivers/mtd/devices/m25p80.c > @@ -128,7 +128,12 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len, > op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8; > > while (remaining) { > - op.data.nbytes = remaining < UINT_MAX ? remaining : UINT_MAX; > + op.data.nbytes = min3(remaining, > + spi_max_transfer_size(flash->spimem->spi), > + spi_max_message_size(flash->spimem->spi) - > + sizeof(op.cmd.opcode) - > + op.addr.nbytes - > + op.dummy.nbytes); Nope, this sort of things should go in the SPI controller driver ->adjust_op_size() hook or directly in spi_mem_adjust_op_size() if it's generic enough (which doesn't seem to be the case since your not counting the opcode, addr and dummy bytes in the message length). Regards, Boris