mmc: core: let the dma map ops handle bouncing

Just like we do for all other block drivers. Especially as the limit
imposed at the moment might be way to pessimistic for iommus.

This also means we are not going to set a bounce limit for the queue, in
case we have a dma mask. On most architectures it was never needed, the
major hold out was x86-32 with PAE, but that has been fixed by now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 92900a095796cc2d0705a5b0448236332076936f..4bf9cd881bd030e040539f1e1cf34f42f83e070c 100644 (file)
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -354,18 +354,15 @@ static const struct blk_mq_ops mmc_mq_ops = {
 static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
 {
        struct mmc_host *host = card->host;
-       u64 limit = BLK_BOUNCE_HIGH;
        unsigned block_size = 512;
 
-       if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
-               limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
-
        blk_queue_flag_set(QUEUE_FLAG_NONROT, mq->queue);
        blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, mq->queue);
        if (mmc_can_erase(card))
                mmc_queue_setup_discard(mq->queue, card);
 
-       blk_queue_bounce_limit(mq->queue, limit);
+       if (!mmc_dev(host)->dma_mask || !*mmc_dev(host)->dma_mask)
+               blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
        blk_queue_max_hw_sectors(mq->queue,
                min(host->max_blk_count, host->max_req_size / 512));
        blk_queue_max_segments(mq->queue, host->max_segs);