[PATCH] Mini-OS: netfront: fix off-by-one error introduced in 7c8f3483

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

7c8f3483 introduced a break within a loop in netfront.c such that
cons and nr_consumed were no longer always being incremented. The
offset at cons will be processed multiple times with the break in
place.

This commit reverts to using the "some" variable in the loop condition,
but avoids ifdefs for the non-libc case. It also renames it to dobreak
to make its usage clearer.

Suggested-by: Sarah Newman <srn@prgmr.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Tested-by: Sarah Newman <srn@prgmr.com>
---
 netfront.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/netfront.c b/netfront.c
index 0eca5b5..b8fac62 100644
--- a/netfront.c
+++ b/netfront.c
@@ -97,19 +97,15 @@ void network_rx(struct netfront_dev *dev)
 {
     RING_IDX rp,cons,req_prod;
     int nr_consumed, more, i, notify;
-#ifdef HAVE_LIBC
-    int some;
-#endif
+    int dobreak;
 
     nr_consumed = 0;
 moretodo:
     rp = dev->rx.sring->rsp_prod;
     rmb(); /* Ensure we see queued responses up to 'rp'. */
 
-#ifdef HAVE_LIBC
-    some = 0;
-#endif
-    for (cons = dev->rx.rsp_cons; cons != rp; nr_consumed++, cons++)
+    dobreak = 0;
+    for (cons = dev->rx.rsp_cons; cons != rp && !dobreak; nr_consumed++, cons++)
     {
         struct net_buffer* buf;
         unsigned char* page;
@@ -134,8 +130,8 @@ moretodo:
 		    len = dev->len;
 		memcpy(dev->data, page+rx->offset, len);
 		dev->rlen = len;
-		some = 1;
-                break;
+		/* No need to receive the rest for now */
+		dobreak = 1;
 	    } else
 #endif
 		dev->netif_rx(page+rx->offset,rx->status);
@@ -144,11 +140,7 @@ moretodo:
     dev->rx.rsp_cons=cons;
 
     RING_FINAL_CHECK_FOR_RESPONSES(&dev->rx,more);
-#ifdef HAVE_LIBC
-    if(more && !some) goto moretodo;
-#else
-    if(more) goto moretodo;
-#endif
+    if(more && !dobreak) goto moretodo;
 
     req_prod = dev->rx.req_prod_pvt;
 
-- 
2.8.0.rc3


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