1 files changed, 14 insertions, 2 deletions

diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index c77eb49eda0e..3b15884e435c 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -30,9 +30,9 @@
 static int mmc_prep_request(struct request_queue *q, struct request *req)
 {
         /*
-         * We only like normal block requests.
+         * We only like normal block requests and discards.
          */
-        if (req->cmd_type != REQ_TYPE_FS) {
+        if (req->cmd_type != REQ_TYPE_FS && !(req->cmd_flags & REQ_DISCARD)) {
                 blk_dump_rq_flags(req, "MMC bad request");
                 return BLKPREP_KILL;
         }
@@ -130,6 +130,18 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock
         blk_queue_prep_rq(mq->queue, mmc_prep_request);
         blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN);
         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
+        if (mmc_can_erase(card)) {
+                queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mq->queue);
+                mq->queue->limits.max_discard_sectors = UINT_MAX;
+                if (card->erased_byte == 0)
+                        mq->queue->limits.discard_zeroes_data = 1;
+                if (!mmc_can_trim(card) && is_power_of_2(card->erase_size)) {
+                        mq->queue->limits.discard_granularity =
+                                                        card->erase_size << 9;
+                        mq->queue->limits.discard_alignment =
+                                                        card->erase_size << 9;
+                }
+        }
 
 #ifdef CONFIG_MMC_BLOCK_BOUNCE
         if (host->max_hw_segs == 1) {