On read, we don't need to sync the whole scatterlist and then check whether any segments need copying - if we check first, we avoid potentially expensive cache handling.
Signed-off-by: Russell King <[email protected]> --- drivers/mmc/host/sdhci.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 7e2f24ac579b..078bf43b4aae 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -602,6 +602,7 @@ static void sdhci_adma_table_post(struct sdhci_host *host, u8 *align; char *buffer; unsigned long flags; + bool has_unaligned; if (data->flags & MMC_DATA_READ) direction = DMA_FROM_DEVICE; @@ -614,7 +615,15 @@ static void sdhci_adma_table_post(struct sdhci_host *host, dma_unmap_single(mmc_dev(host->mmc), host->align_addr, 128 * 4, direction); - if (data->flags & MMC_DATA_READ) { + /* Do a quick scan of the SG list for any unaligned mappings */ + has_unaligned = false; + for_each_sg(data->sg, sg, host->sg_count, i) + if (sg_dma_address(sg) & 3) { + has_unaligned = true; + break; + } + + if (has_unaligned && data->flags & MMC_DATA_READ) { dma_sync_sg_for_cpu(mmc_dev(host->mmc), data->sg, data->sg_len, direction); -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
