usb: langwell_udc: fix big file transfer issue.

This patch fixing the problem with large file transfers failing. Swap the read
order to avoid unexpected RX status.

Signed-off-by: Christophe Lebouc <christophex.lebouc@intel.com>
Signed-off-by: Hao Wu <hao.wu@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/usb/gadget/langwell_udc.c b/drivers/usb/gadget/langwell_udc.c
index d297f9eb92e4..064306046702 100644
--- a/drivers/usb/gadget/langwell_udc.c
+++ b/drivers/usb/gadget/langwell_udc.c
@@ -2440,12 +2440,14 @@ static int process_ep_req(struct langwell_udc *dev, int index,
         dev_vdbg(&dev->pdev->dev, "---> %s()\n", __func__);
 
         for (i = 0; i < curr_req->dtd_count; i++) {
-                remaining_length = le16_to_cpu(curr_dtd->dtd_total);
-                actual -= remaining_length;
 
                 /* command execution states by dTD */
                 dtd_status = curr_dtd->dtd_status;
 
+                barrier();
+                remaining_length = le16_to_cpu(curr_dtd->dtd_total);
+                actual -= remaining_length;
+
                 if (!dtd_status) {
                         /* transfers completed successfully */
                         if (!remaining_length) {