mmc_block: be prepared for oversized requests

The block layer does not support very low sector count restrictions
so we need to be prepared to handle bigger requests than we can send
directly to the controller.

Problem found by Manuel Lauss.

Signed-off-by: Pierre Ossman <pierre@ossman.eu>

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index fe8041e619eabec7029a12c8f7c0983e2a56346c..b25e9b6516ae6942d6e9a0c34fc3f0dba0f9556a 100644 (file)
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -253,6 +253,14 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
                brq.stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
                brq.data.blocks = req->nr_sectors;
 
+               /*
+                * The block layer doesn't support all sector count
+                * restrictions, so we need to be prepared for too big
+                * requests.
+                */
+               if (brq.data.blocks > card->host->max_blk_count)
+                       brq.data.blocks = card->host->max_blk_count;
+
                /*
                 * After a read error, we redo the request one sector at a time
                 * in order to accurately determine which sectors can be read