[Qemu-devel] [PATCH v2 1/2] net: assert that tx packets have nonzero size

[Oleinik, Alexander]

Virtual devices should not try to send zero-sized packets. The caller
should check the size prior to calling qemu_sendv_packet_async.

Signed-off-by: Alexander Oleinik <address@hidden>
---
v2:
  * Improve the comment to explain the rationale for adding the assert.
 net/net.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/net.c b/net/net.c
index 7d4098254f..4ad21df36f 100644
--- a/net/net.c
+++ b/net/net.c
@@ -741,6 +741,15 @@ ssize_t qemu_sendv_packet_async(NetClientState *sender,
     size_t size = iov_size(iov, iovcnt);
     int ret;
 
+    /*
+     * Since this function returns the size of the sent packets, and a return
+     * value of zero indicates that the packet will be sent asynchronously,
+     * there is currently no way to report that a 0-sized packet has been sent
+     * successfully. Forbid it for now, and if someone needs this functionality
+     * later, the API will require a change.
+     */
+    assert(size);
+
     if (size > NET_BUFSIZE) {
         return size;
     }
-- 
2.20.1