staging: comedi: drivers: usbduxfast.c: fix for DMA buffers on stack

fix for instances of DMA buffer on stack(being passed to usb_control_msg) for
the USB-DUXfast Board driver.

Signed-off-by: Kumar Amit Mehta <gmate.amit@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/usbduxfast.c b/drivers/staging/comedi/drivers/usbduxfast.c
index 4bf5dd094dc9da043b2aea8302c6638e229cf926..1ba0e3df492d1e9ceeedcebe4af3e85b82a08491 100644 (file)
--- a/drivers/staging/comedi/drivers/usbduxfast.c
+++ b/drivers/staging/comedi/drivers/usbduxfast.c
@@ -436,10 +436,14 @@ static void usbduxfastsub_ai_Irq(struct urb *urb)
 static int usbduxfastsub_start(struct usbduxfastsub_s *udfs)
 {
        int ret;
-       unsigned char local_transfer_buffer[16];
+       unsigned char *local_transfer_buffer;
+
+       local_transfer_buffer = kmalloc(1, GFP_KERNEL);
+       if (!local_transfer_buffer)
+               return -ENOMEM;
 
        /* 7f92 to zero */
-       local_transfer_buffer[0] = 0;
+       *local_transfer_buffer = 0;
        /* bRequest, "Firmware" */
        ret = usb_control_msg(udfs->usbdev, usb_sndctrlpipe(udfs->usbdev, 0),
                              USBDUXFASTSUB_FIRMWARE,
@@ -450,22 +454,25 @@ static int usbduxfastsub_start(struct usbduxfastsub_s *udfs)
                              local_transfer_buffer,
                              1,      /* Length */
                              EZTIMEOUT);    /* Timeout */
-       if (ret < 0) {
+       if (ret < 0)
                dev_err(&udfs->interface->dev,
                        "control msg failed (start)\n");
-               return ret;
-       }
 
-       return 0;
+       kfree(local_transfer_buffer);
+       return ret;
 }
 
 static int usbduxfastsub_stop(struct usbduxfastsub_s *udfs)
 {
        int ret;
-       unsigned char local_transfer_buffer[16];
+       unsigned char *local_transfer_buffer;
+
+       local_transfer_buffer = kmalloc(1, GFP_KERNEL);
+       if (!local_transfer_buffer)
+               return -ENOMEM;
 
        /* 7f92 to one */
-       local_transfer_buffer[0] = 1;
+       *local_transfer_buffer = 1;
        /* bRequest, "Firmware" */
        ret = usb_control_msg(udfs->usbdev, usb_sndctrlpipe(udfs->usbdev, 0),
                              USBDUXFASTSUB_FIRMWARE,
@@ -474,13 +481,12 @@ static int usbduxfastsub_stop(struct usbduxfastsub_s *udfs)
                              0x0000,   /* Index */
                              local_transfer_buffer, 1, /* Length */
                              EZTIMEOUT);       /* Timeout */
-       if (ret < 0) {
+       if (ret < 0)
                dev_err(&udfs->interface->dev,
                        "control msg failed (stop)\n");
-               return ret;
-       }
 
-       return 0;
+       kfree(local_transfer_buffer);
+       return ret;
 }
 
 static int usbduxfastsub_upload(struct usbduxfastsub_s *udfs,