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[73.242.244.99]) by smtp.gmail.com with ESMTPSA id 139sm1805554itk.28.2019.03.20.15.43.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Mar 2019 15:43:59 -0700 (PDT) From: George Hilliard To: Greg Kroah-Hartman Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, George Hilliard Subject: [PATCH v3 3/3] staging: mt7621-mmc: Check for nonzero number of scatterlist entries Date: Wed, 20 Mar 2019 16:42:05 -0600 Message-Id: <20190320224204.10243-4-thirtythreeforty@gmail.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190320224204.10243-1-thirtythreeforty@gmail.com> References: <20190320224204.10243-1-thirtythreeforty@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The buffer descriptor setup loop is correct only if it is setting up at least one bd struct. Besides, there is an error if dma_map_sg() returns 0, which is possible and must be handled. Additionally, remove the BUG_ON() checking sglen, which is unnecessary because we configure DMA with that constraint during init. Signed-off-by: George Hilliard --- v2: Rebased v1 v3: Remove existing and added BUG_ON() in v2, and handle dma_map_sg failure gracefully. drivers/staging/mt7621-mmc/sd.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/staging/mt7621-mmc/sd.c b/drivers/staging/mt7621-mmc/sd.c index 139533606863..cf2ad06112eb 100644 --- a/drivers/staging/mt7621-mmc/sd.c +++ b/drivers/staging/mt7621-mmc/sd.c @@ -593,8 +593,6 @@ static void msdc_dma_setup(struct msdc_host *host, struct msdc_dma *dma, struct bd *bd; u32 j; - BUG_ON(sglen > MAX_BD_NUM); /* not support currently */ - gpd = dma->gpd; bd = dma->bd; @@ -687,6 +685,13 @@ static int msdc_do_request(struct mmc_host *mmc, struct mmc_request *mrq) data->sg_count = dma_map_sg(mmc_dev(mmc), data->sg, data->sg_len, mmc_get_dma_dir(data)); + + if (data->sg_count == 0) { + dev_err(mmc_dev(host->mmc), "failed to map DMA for transfer\n"); + data->error = -ENOMEM; + goto done; + } + msdc_dma_setup(host, &host->dma, data->sg, data->sg_count); -- 2.21.0