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 <rmk+kernel@xxxxxxxxxxxxxxxx>
=-DO NOT APPLY-=
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 bcf4f9ec0ea4..e918e17c39e4 100644
=-DO NOT APPLY-= a/drivers/mmc/host/sdhci.c
=+DO NOT APPLY+= 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;
=+DO NOT APPLY+= 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 NOT APPLY+= /* Do a quick scan of the SG list for any unaligned mappings */
=+DO NOT APPLY+= has_unaligned = false;
=+DO NOT APPLY+= for_each_sg(data->sg, sg, host->sg_count, i)
=+DO NOT APPLY+= if (sg_dma_address(sg) & 3) {
=+DO NOT APPLY+= has_unaligned = true;
=+DO NOT APPLY+= break;
=+DO NOT APPLY+= }
=+DO NOT APPLY+=
=+DO NOT APPLY+= 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
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