Commit 771a3dc2 authored Jan 26, 2016 by Russell King Committed by Ulf Hansson Feb 29, 2016

mmc: sdhci: further fix for DMA unmapping in sdhci_post_req()



sdhci_post_req() exists to unmap a previously mapped but already
finished request, while the next request is in progress.  However, the
state of the SDHCI_REQ_USE_DMA flag depends on the last submitted
request.

This means we can end up clearing the flag due to a quirk, which then
means that sdhci_post_req() fails to unmap the DMA buffer, potentially
leading to data corruption.

We can safely ignore the SDHCI_REQ_USE_DMA here, as testing
data->host_cookie is entirely sufficient.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[ Re-based to apply as a separate fix ]
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.5+
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

parent 0ca33b4a

drivers/mmc/host/sdhci.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -2084,15 +2084,14 @@ static void sdhci_post_req(struct mmc_host mmc, struct mmc_request mrq,
		struct sdhci_host *host = mmc_priv(mmc);
		struct mmc_data *data = mrq->data;

		if (host->flags & SDHCI_REQ_USE_DMA) {
		if (data->host_cookie == COOKIE_GIVEN \|\|
		data->host_cookie == COOKIE_MAPPED)
		dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
		data->flags & MMC_DATA_WRITE ?
		DMA_TO_DEVICE : DMA_FROM_DEVICE);

		data->host_cookie = COOKIE_UNMAPPED;
		}
		}

		static int sdhci_pre_dma_transfer(struct sdhci_host *host,
		struct mmc_data *data)

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