[PATCH v4] staging: gdm724x: Fix DMA from stack

[Amey Narkhede]

Stack allocated buffers cannot be used for DMA
on all architectures so allocate hci_packet buffer
using kmalloc.

Signed-off-by: Amey Narkhede <ameynarkhed...@gmail.com>
---
Changes in v4:
        - Use struct_size to allocate memory for hci_packet
        - Fix memory corruption

 drivers/staging/gdm724x/gdm_usb.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/gdm724x/gdm_usb.c 
b/drivers/staging/gdm724x/gdm_usb.c
index dc4da66c3..54bdb64f5 100644
--- a/drivers/staging/gdm724x/gdm_usb.c
+++ b/drivers/staging/gdm724x/gdm_usb.c
@@ -56,20 +56,24 @@ static int gdm_usb_recv(void *priv_dev,

 static int request_mac_address(struct lte_udev *udev)
 {
-       u8 buf[16] = {0,};
-       struct hci_packet *hci = (struct hci_packet *)buf;
+       struct hci_packet *hci;
        struct usb_device *usbdev = udev->usbdev;
        int actual;
        int ret = -1;

+       hci = kmalloc(struct_size(hci, data, 1), GFP_KERNEL);
+       if (!hci)
+               return -ENOMEM;
+
        hci->cmd_evt = gdm_cpu_to_dev16(udev->gdm_ed, LTE_GET_INFORMATION);
        hci->len = gdm_cpu_to_dev16(udev->gdm_ed, 1);
        hci->data[0] = MAC_ADDRESS;

-       ret = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 2), buf, 5,
+       ret = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 2), hci, 5,
                           &actual, 1000);

        udev->request_mac_addr = 1;
+       kfree(hci);

        return ret;
 }
--
2.30.1