mmc: enforce correct sg list

Now that we've fixed our only offender when it comes to strange sg
list, add a check so that future users keep the sg list proper with
regard to transfer size.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 4a73e8b2428d..e8f896c61b34 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -99,6 +99,10 @@ EXPORT_SYMBOL(mmc_request_done);
 void
 mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
 {
+#ifdef CONFIG_MMC_DEBUG
+        unsigned int i, sz;
+#endif
+
         pr_debug("%s: starting CMD%u arg %08x flags %08x\n",
                  mmc_hostname(host), mrq->cmd->opcode,
                  mrq->cmd->arg, mrq->cmd->flags);
@@ -113,6 +117,13 @@ mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
                 BUG_ON(mrq->data->blocks * mrq->data->blksz >
                         host->max_req_size);
 
+#ifdef CONFIG_MMC_DEBUG
+                sz = 0;
+                for (i = 0;i < mrq->data->sg_len;i++)
+                        sz += mrq->data->sg[i].length;
+                BUG_ON(sz != mrq->data->blocks * mrq->data->blksz);
+#endif
+
                 mrq->cmd->data = mrq->data;
                 mrq->data->error = 0;
                 mrq->data->mrq = mrq;