Input: sur40 - fix DMA on stack

During the initialisation the driver uses a buffer on the stack for DMA.
That violates the cache coherency rules. The fix is to allocate the buffer
with kmalloc().

Signed-off-by: Oliver Neukum <ONeukum@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 14 insertions, 7 deletions

diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c
index b6c4d03de340..880c40b23f66 100644
--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c
@@ -197,28 +197,34 @@ static int sur40_command(struct sur40_state *dev,
 static int sur40_init(struct sur40_state *dev)
 {
         int result;
-        u8 buffer[24];
+        u8 *buffer;
+
+        buffer = kmalloc(24, GFP_KERNEL);
+        if (!buffer) {
+                result = -ENOMEM;
+                goto error;
+        }
 
         /* stupidly replay the original MS driver init sequence */
         result = sur40_command(dev, SUR40_GET_VERSION, 0x00, buffer, 12);
         if (result < 0)
-                return result;
+                goto error;
 
         result = sur40_command(dev, SUR40_GET_VERSION, 0x01, buffer, 12);
         if (result < 0)
-                return result;
+                goto error;
 
         result = sur40_command(dev, SUR40_GET_VERSION, 0x02, buffer, 12);
         if (result < 0)
-                return result;
+                goto error;
 
         result = sur40_command(dev, SUR40_UNKNOWN2,    0x00, buffer, 24);
         if (result < 0)
-                return result;
+                goto error;
 
         result = sur40_command(dev, SUR40_UNKNOWN1,    0x00, buffer,  5);
         if (result < 0)
-                return result;
+                goto error;
 
         result = sur40_command(dev, SUR40_GET_VERSION, 0x03, buffer, 12);
 
@@ -226,7 +232,8 @@ static int sur40_init(struct sur40_state *dev)
          * Discard the result buffer - no known data inside except
          * some version strings, maybe extract these sometime...
          */
-
+error:
+        kfree(buffer);
         return result;
 }