mmc: block: Don't do single-sector reads during recovery #5036
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See raspberrypi#5019 If an SD card has degraded performance such that IO operations time out then the MMC block layer will leak SG DMA mappings in the swiotlb during recovery. It retries the same SG and this causes the leak, as it is mapped twice - once in sdhci_pre_req() and again during single-block reads in sdhci_prepare_data(). Resetting the card (including power-cycling if a regulator for vmmc is present) ought to be enough to recover a stuck state, so for now don't try single-block reads in the recovery path. Signed-off-by: Jonathan Bell <[email protected]>
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See #5019
If an SD card has degraded performance such that IO operations time out
then the MMC block layer will leak SG DMA mappings during recovery. It
retries the same SG and this causes the leak, as it is mapped twice -
once in sdhci_pre_req() and again during single-block reads in
sdhci_prepare_data().
Resetting the card (including power-cycling if a regulator for vmmc is
present) ought to be enough to recover a stuck state, so for now remove
the call to mmc_blk_read_single().
Signed-off-by: Jonathan Bell [email protected]