Commit f5de4699 authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google) Committed by Ulf Hansson
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mtk-sd: Prevent memory corruption from DMA map failure 



If msdc_prepare_data() fails to map the DMA region, the request is
not prepared for data receiving, but msdc_start_data() proceeds
the DMA with previous setting.
Since this will lead a memory corruption, we have to stop the
request operation soon after the msdc_prepare_data() fails to
prepare it.

Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Fixes: 20848903 ("mmc: mediatek: Add Mediatek MMC driver")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/174972756982.3337526.6755001617701603082.stgit@mhiramat.tok.corp.google.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 539d8057

drivers/mmc/host/mtk-sd.c

+16 −1
Original line number Diff line number Diff line
@@ -853,6 +853,11 @@ static void msdc_prepare_data(struct msdc_host *host, struct mmc_data *data) 
	}

}



static bool msdc_data_prepared(struct mmc_data *data)

{

	return data->host_cookie & MSDC_PREPARE_FLAG;

}



static void msdc_unprepare_data(struct msdc_host *host, struct mmc_data *data)

{

	if (data->host_cookie & MSDC_ASYNC_FLAG)
@@ -1484,8 +1489,18 @@ static void msdc_ops_request(struct mmc_host *mmc, struct mmc_request *mrq) 
	WARN_ON(!host->hsq_en && host->mrq);

	host->mrq = mrq;



	if (mrq->data)

	if (mrq->data) {

		msdc_prepare_data(host, mrq->data);

		if (!msdc_data_prepared(mrq->data)) {

			/*

			 * Failed to prepare DMA area, fail fast before

			 * starting any commands.

			 */

			mrq->cmd->error = -ENOSPC;

			mmc_request_done(mmc_from_priv(host), mrq);

			return;

		}

	}



	/* if SBC is required, we have HW option and SW option.

	 * if HW option is enabled, and SBC does not have "special" flags,