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=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 EEFB6C4332B for ; Tue, 12 Jan 2021 13:14:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2AEB22CAF for ; Tue, 12 Jan 2021 13:14:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733288AbhALNO3 (ORCPT ); Tue, 12 Jan 2021 08:14:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:54632 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404086AbhALM5o (ORCPT ); Tue, 12 Jan 2021 07:57:44 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 054432313A; Tue, 12 Jan 2021 12:56:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610456172; bh=byiYvvTnmGUoUR8k/HrJGd3sxguP1G+iK44YQb320ig=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W8EiMvW3Vhho/DRULq45qK43uOrofv7veSw7jDklsFM3nK46UR4KIZywrWNUeAd+k 88nZUNsw93JG5kpU5qqMtdb13XP4L2WK+8KMJ4mcKVsw9RMDGsVYHhgUslk2RkSi6G bOOuYdwepU6Bi7wV7BYVg6ncrlgkFQcjhYmQTKjiTOXM1r4tGMzFcr/6o8CP7I4ATc UqyCG16HVUkh4mrABMUmnK/6Z5wvRzu8it89+XRmY+I/mxGNJIwo+6A7xjmf2oaNWD x8gHnO9WXXE+uzlRh/DKHYjMX8NIRGMCnlhyUOO0R0cZOoO7c60hAQMuqsIG4rIDZB buSS2EaDucaoA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Xu Yilun , Mark Brown , Sasha Levin , linux-spi@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 29/51] spi: fix the divide by 0 error when calculating xfer waiting time Date: Tue, 12 Jan 2021 07:55:11 -0500 Message-Id: <20210112125534.70280-29-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210112125534.70280-1-sashal@kernel.org> References: <20210112125534.70280-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xu Yilun [ Upstream commit 6170d077bf92c5b3dfbe1021688d3c0404f7c9e9 ] The xfer waiting time is the result of xfer->len / xfer->speed_hz. This patch makes the assumption of 100khz xfer speed if the xfer->speed_hz is not assigned and stays 0. This avoids the divide by 0 issue and ensures a reasonable tolerant waiting time. Signed-off-by: Xu Yilun Link: https://lore.kernel.org/r/1609723749-3557-1-git-send-email-yilun.xu@intel.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 2eaa7dbb70108..7694e1ae5b0b2 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1100,6 +1100,7 @@ static int spi_transfer_wait(struct spi_controller *ctlr, { struct spi_statistics *statm = &ctlr->statistics; struct spi_statistics *stats = &msg->spi->statistics; + u32 speed_hz = xfer->speed_hz; unsigned long long ms; if (spi_controller_is_slave(ctlr)) { @@ -1108,8 +1109,11 @@ static int spi_transfer_wait(struct spi_controller *ctlr, return -EINTR; } } else { + if (!speed_hz) + speed_hz = 100000; + ms = 8LL * 1000LL * xfer->len; - do_div(ms, xfer->speed_hz); + do_div(ms, speed_hz); ms += ms + 200; /* some tolerance */ if (ms > UINT_MAX) -- 2.27.0