mmc: at91_mci: fix pointer errors

Fixes two pointer errors, one which leads to memory overwrites if used
with large chunks of data.

Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Andrew Victor <avictor.za@gmail.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/mmc/host/at91_mci.c b/drivers/mmc/host/at91_mci.c
index 63924e0c7ea9..4e1b2e6288da 100644
--- a/drivers/mmc/host/at91_mci.c
+++ b/drivers/mmc/host/at91_mci.c
@@ -227,11 +227,13 @@ static inline void at91_mci_sg_to_dma(struct at91mci_host *host, struct mmc_data
                         for (index = 0; index < (amount / 4); index++)
                                 *dmabuf++ = swab32(sgbuffer[index]);
                 } else {
-                        memcpy(dmabuf, sgbuffer, amount);
-                        dmabuf += amount;
+                        char *tmpv = (char *)dmabuf;
+                        memcpy(tmpv, sgbuffer, amount);
+                        tmpv += amount;
+                        dmabuf = (unsigned *)tmpv;
                 }
 
-                kunmap_atomic(sgbuffer, KM_BIO_SRC_IRQ);
+                kunmap_atomic(((void *)sgbuffer) - sg->offset, KM_BIO_SRC_IRQ);
 
                 if (size == 0)
                         break;