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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 598D8C4646B for ; Mon, 1 Mar 2021 22:42:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FA3460201 for ; Mon, 1 Mar 2021 22:42:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245727AbhCAWgf (ORCPT ); Mon, 1 Mar 2021 17:36:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:58254 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238708AbhCARiE (ORCPT ); Mon, 1 Mar 2021 12:38:04 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2BBDA64F70; Mon, 1 Mar 2021 16:55:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614617747; bh=NokzAIon6kmeZtdv//49L+fvLawV7xl3oTAlaAIr8kw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X3+5am7z8sNOkchHN73KPZtWd1W7s4M7zdT6JTos3no6ikIMt9ne65ITASDtsZcSP 7W6KdIZsUpMNR2Uz+TfpY70VQ7gSYV3WMWvSEqyX2cj7BDfr95ZSJQsI45/+nEmSRX ipfOBMNAoznbqWOERXYkF9Fm1c8q04U/7HAb5hi0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alain Volmat , Mark Brown , Sasha Levin Subject: [PATCH 5.4 182/340] spi: stm32: properly handle 0 byte transfer Date: Mon, 1 Mar 2021 17:12:06 +0100 Message-Id: <20210301161057.265251020@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161048.294656001@linuxfoundation.org> References: <20210301161048.294656001@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alain Volmat [ Upstream commit 2269f5a8b1a7b38651d62676b98182828f29d11a ] On 0 byte transfer request, return straight from the xfer function after finalizing the transfer. Fixes: dcbe0d84dfa5 ("spi: add driver for STM32 SPI controller") Signed-off-by: Alain Volmat Link: https://lore.kernel.org/r/1612551572-495-2-git-send-email-alain.volmat@foss.st.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-stm32.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index 77ddf23b65d65..8622cf9d3f640 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -1668,6 +1668,10 @@ static int stm32_spi_transfer_one(struct spi_master *master, struct stm32_spi *spi = spi_master_get_devdata(master); int ret; + /* Don't do anything on 0 bytes transfers */ + if (transfer->len == 0) + return 0; + spi->tx_buf = transfer->tx_buf; spi->rx_buf = transfer->rx_buf; spi->tx_len = spi->tx_buf ? transfer->len : 0; -- 2.27.0