[PATCH] mci: dove: fix dereference of nullable pointer

[Ahmad Fatoum]

data->{blocks, blocksize, flags} are all used outside of the if clause
checking whether data is not NULL.
Fix this to avoid dereferencing null pointers.

Fixes: bdcf89d274 ("mci: add Marvell Dove SDHCI driver")
Cc: Michael Grzeschik <m.grzesc...@pengutronix.de>
Signed-off-by: Ahmad Fatoum <ah...@a3f.at>
---
 drivers/mci/dove-sdhci.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/mci/dove-sdhci.c b/drivers/mci/dove-sdhci.c
index e71a27ce4f33..bccda5399491 100644
--- a/drivers/mci/dove-sdhci.c
+++ b/drivers/mci/dove-sdhci.c
@@ -116,7 +116,7 @@ static int dove_sdhci_mci_send_cmd(struct mci_host *mci, 
struct mci_cmd *cmd,
        u32 command, xfer;
        u64 start;
        int ret;
-       unsigned int num_bytes = data->blocks * data->blocksize;
+       unsigned int num_bytes = 0;
        struct dove_sdhci *host = priv_from_mci_host(mci);
 
        sdhci_write32(&host->sdhci, SDHCI_INT_STATUS, ~0);
@@ -140,6 +140,7 @@ static int dove_sdhci_mci_send_cmd(struct mci_host *mci, 
struct mci_cmd *cmd,
 
        /* setup transfer data */
        if (data) {
+               num_bytes = data->blocks * data->blocksize;
                if (data->flags & MMC_DATA_READ)
                        sdhci_write32(&host->sdhci, SDHCI_DMA_ADDRESS, 
(u32)data->dest);
                else
@@ -178,14 +179,14 @@ static int dove_sdhci_mci_send_cmd(struct mci_host *mci, 
struct mci_cmd *cmd,
 
        sdhci_read_response(&host->sdhci, cmd);
 
-       if (data->flags & MMC_DATA_WRITE)
-               dma_sync_single_for_cpu((unsigned long)data->src,
-                                        num_bytes, DMA_TO_DEVICE);
-       else
-               dma_sync_single_for_cpu((unsigned long)data->dest,
+       if (data) {
+               if (data->flags & MMC_DATA_WRITE)
+                       dma_sync_single_for_cpu((unsigned long)data->src,
+                                               num_bytes, DMA_TO_DEVICE);
+               else
+                       dma_sync_single_for_cpu((unsigned long)data->dest,
                                         num_bytes, DMA_FROM_DEVICE);
 
-       if (data) {
                ret = dove_sdhci_wait_for_done(host, SDHCI_INT_XFER_COMPLETE);
                if (ret) {
                        dev_err(host->mci.hw_dev, "error while transfering data 
for command %d\n",
-- 
2.20.1


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