From patchwork Sat Nov 2 13:31:25 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 3131201 Return-Path: X-Original-To: patchwork-linux-media@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 6638E9F244 for ; Sat, 2 Nov 2013 16:34:42 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CDCCC20375 for ; Sat, 2 Nov 2013 16:34:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 386362035C for ; Sat, 2 Nov 2013 16:34:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753977Ab3KBQeb (ORCPT ); Sat, 2 Nov 2013 12:34:31 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:60772 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753566Ab3KBQdp (ORCPT ); Sat, 2 Nov 2013 12:33:45 -0400 Received: from [177.143.133.66] (helo=smtp.w2.samsung.com) by bombadil.infradead.org with esmtpsa (Exim 4.80.1 #2 (Red Hat Linux)) id 1Vce8q-0008KN-1v; Sat, 02 Nov 2013 16:33:40 +0000 Received: from mchehab by smtp.w2.samsung.com with local (Exim 4.80.1) (envelope-from ) id 1VcbIh-000333-8G; Sat, 02 Nov 2013 11:31:39 -0200 From: Mauro Carvalho Chehab Cc: Mauro Carvalho Chehab , Linux Media Mailing List , Mauro Carvalho Chehab , Manu Abraham , Alexey Khoroshilov , Andreas Regel Subject: [PATCHv2 17/29] stv090x: Don't use dynamic static allocation Date: Sat, 2 Nov 2013 11:31:25 -0200 Message-Id: <1383399097-11615-18-git-send-email-m.chehab@samsung.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1383399097-11615-1-git-send-email-m.chehab@samsung.com> References: <1383399097-11615-1-git-send-email-m.chehab@samsung.com> To: unlisted-recipients:; (no To-header on input) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Dynamic static allocation is evil, as Kernel stack is too low, and compilation complains about it on some archs: drivers/media/dvb-frontends/stv090x.c:750:1: warning: 'stv090x_write_regs.constprop.6' uses dynamic stack allocation [enabled by default] Instead, let's enforce a limit for the buffer. Considering that I2C transfers are generally limited, and that devices used on USB has a max data length of 80, it seem safe to use 80 as the hard limit for all those devices. On most cases, the limit is a way lower than that, but 80 is small enough to not affect the Kernel stack, and it is a no brain limit, as using smaller ones would require to either carefully each driver or to take a look on each datasheet. Signed-off-by: Mauro Carvalho Chehab Cc: Manu Abraham Cc: Alexey Khoroshilov Cc: Andreas Regel --- drivers/media/dvb-frontends/stv090x.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/media/dvb-frontends/stv090x.c b/drivers/media/dvb-frontends/stv090x.c index 56d470ad5a82..7484b01a9f13 100644 --- a/drivers/media/dvb-frontends/stv090x.c +++ b/drivers/media/dvb-frontends/stv090x.c @@ -722,9 +722,16 @@ static int stv090x_write_regs(struct stv090x_state *state, unsigned int reg, u8 { const struct stv090x_config *config = state->config; int ret; - u8 buf[2 + count]; + u8 buf[80]; struct i2c_msg i2c_msg = { .addr = config->address, .flags = 0, .buf = buf, .len = 2 + count }; + if (2 + count > sizeof(buf)) { + printk(KERN_WARNING + "%s: i2c wr reg=%04x: len=%d is too big!\n", + KBUILD_MODNAME, reg, count); + return -EREMOTEIO; + } + buf[0] = reg >> 8; buf[1] = reg & 0xff; memcpy(&buf[2], data, count);