net: move the tap buffer into TAPState

KVM uses a 64k buffer for reading from tapfd (for GSO support)
and allocates the buffer with TAPState rather than on the stack.

Not allocating it on the stack probably makes sense for qemu
anyway, so merge it in advance of GSO support.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>

diff --git a/net.c b/net.c
index da18f0f..443f769 100644 (file)
--- a/net.c
+++ b/net.c
@@ -921,6 +921,7 @@ typedef struct TAPState {
     int fd;
     char down_script[1024];
     char down_script_arg[128];
+    uint8_t buf[4096];
 } TAPState;
 
 static int launch_script(const char *setup_script, const char *ifname, int fd);
@@ -972,12 +973,11 @@ static ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
 static void tap_send(void *opaque)
 {
     TAPState *s = opaque;
-    uint8_t buf[4096];
     int size;
 
-    size = tap_read_packet(s->fd, buf, sizeof(buf));
+    size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
     if (size > 0) {
-        qemu_send_packet(s->vc, buf, size);
+        qemu_send_packet(s->vc, s->buf, size);
     }
 }