1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
index 9ed3e741bee1..10f3205798e8 100644
--- a/drivers/usb/mon/mon_bin.c
+++ b/drivers/usb/mon/mon_bin.c
@@ -348,12 +348,12 @@ static unsigned int mon_buff_area_alloc_contiguous(struct mon_reader_bin *rp,
 
 /*
  * Return a few (kilo-)bytes to the head of the buffer.
- * This is used if a DMA fetch fails.
+ * This is used if a data fetch fails.
  */
 static void mon_buff_area_shrink(struct mon_reader_bin *rp, unsigned int size)
 {
 
-        size = (size + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
+        /* size &= ~(PKT_ALIGN-1);  -- we're called with aligned size */
         rp->b_cnt -= size;
         if (rp->b_in < size)
                 rp->b_in += rp->b_size;
@@ -433,6 +433,7 @@ static void mon_bin_event(struct mon_reader_bin *rp, struct urb *urb,
         unsigned int urb_length;
         unsigned int offset;
         unsigned int length;
+        unsigned int delta;
         unsigned int ndesc, lendesc;
         unsigned char dir;
         struct mon_bin_hdr *ep;
@@ -537,8 +538,10 @@ static void mon_bin_event(struct mon_reader_bin *rp, struct urb *urb,
         if (length != 0) {
                 ep->flag_data = mon_bin_get_data(rp, offset, urb, length);
                 if (ep->flag_data != 0) {       /* Yes, it's 0x00, not '0' */
-                        ep->len_cap = 0;
-                        mon_buff_area_shrink(rp, length);
+                        delta = (ep->len_cap + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
+                        ep->len_cap -= length;
+                        delta -= (ep->len_cap + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
+                        mon_buff_area_shrink(rp, delta);
                 }
         } else {
                 ep->flag_data = data_tag;