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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38C80C433F5 for ; Mon, 31 Jan 2022 13:48:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376583AbiAaNsS (ORCPT ); Mon, 31 Jan 2022 08:48:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358762AbiAaNsS (ORCPT ); Mon, 31 Jan 2022 08:48:18 -0500 Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::223]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6892BC061714; Mon, 31 Jan 2022 05:48:17 -0800 (PST) Received: (Authenticated sender: miquel.raynal@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id AF11E60015; Mon, 31 Jan 2022 13:48:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1643636895; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=scmOkaI+TyjdmDOiGryj2VGEm54oTCgShwxEMvffMbI=; b=TYR4x20jM7rkpL42uk3v6X38JHHvKdvx9xC0tvx3KK0ckg4lL/O/Cr785l+KJ8gPTcmDNV RdHs/8edUCO2UoaQ93qfep88JSepBsPZJSDjpab2Af5XtasM0dBX+320Jvw2BCp5bEiski cYI3KvEeMeayMlwrVh5EX7UDpLVY7BicXCSxXeRwQILRQ/fZw1qWQUxJzraUz1qH81R1m5 OE2L4GOEJnI7Ej2mc4Zab/u+y/cFTxuOHvyMw4Bo5ObXF2KYS3H1AfOC9w2ILPCGzDDLt3 RmnQdcDcfTIWlMEHkwHj5S85oPbqjwa9J1qwDJZFg/Te9NSQXWgXBjSQu2aI4A== Date: Mon, 31 Jan 2022 14:48:13 +0100 From: Miquel Raynal To: Pratyush Yadav Cc: Mark Brown , Tudor Ambarus , Michael Walle , Takahiro Kuwano , , Subject: Re: [PATCH] spi: spi-mem: check if data buffers are on stack Message-ID: <20220131144813.725f0736@xps13> In-Reply-To: <20220131114508.1028306-1-p.yadav@ti.com> References: <20220131114508.1028306-1-p.yadav@ti.com> Organization: Bootlin X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org Hi Pratyush, p.yadav@ti.com wrote on Mon, 31 Jan 2022 17:15:08 +0530: > The buffers passed in the data phase must be DMA-able. Programmers often > don't realise this requirement and pass in buffers that reside on the > stack. This can be hard to spot when reviewing code. Reject ops if their > data buffer is on the stack to avoid this. >=20 > Signed-off-by: Pratyush Yadav > --- > drivers/spi/spi-mem.c | 9 +++++++++ > 1 file changed, 9 insertions(+) >=20 > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c > index 37f4443ce9a0..b3793a2979ee 100644 > --- a/drivers/spi/spi-mem.c > +++ b/drivers/spi/spi-mem.c > @@ -207,6 +207,15 @@ static int spi_mem_check_op(const struct spi_mem_op = *op) > !spi_mem_buswidth_is_valid(op->data.buswidth)) > return -EINVAL; > =20 > + /* Buffers must be DMA-able. */ > + if (op->data.dir =3D=3D SPI_MEM_DATA_IN && > + object_is_on_stack(op->data.buf.in)) > + return -EINVAL; > + > + if (op->data.dir =3D=3D SPI_MEM_DATA_OUT && > + object_is_on_stack(op->data.buf.out)) > + return -EINVAL; Definitely a good idea. This change will depend on the spi-mem-ecc series. I will soon merge this branch into mtd/next so that any change that depends on it can be merged in mtd/next directly, if nobody disagrees. Thanks, Miqu=C3=A8l