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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>
This commit is contained in:
Russell King 2016-01-26 13:40:53 +00:00 committed by Ulf Hansson
parent 0ca33b4ad9
commit 771a3dc225
1 changed files with 7 additions and 8 deletions
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15
drivers/mmc/host/sdhci.c
View File

@ -2084,14 +2084,13 @@ 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;
}
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,