[PATCH] net/dump.c: Suppress spurious compiler warning

[Philipp Tomsich <philipp.tomsich@vrull.eu>]

Compiling with gcc version 11.2.0 (Ubuntu 11.2.0-13ubuntu1) results in
a (spurious) warning:

  In function ‘dump_receive_iov’,
      inlined from ‘filter_dump_receive_iov’ at ../net/dump.c:157:5:
  ../net/dump.c:89:9: error: ‘writev’ specified size 18446744073709551600 exceeds maximum object size 9223372036854775807 [-Werror=stringop-overflow=]
     89 |     if (writev(s->fd, dumpiov, cnt + 1) != sizeof(hdr) + caplen) {
        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  In file included from /home/ptomsich/qemu/include/qemu/osdep.h:108,
                   from ../net/dump.c:25:
  ../net/dump.c: In function ‘filter_dump_receive_iov’:
  /usr/include/x86_64-linux-gnu/sys/uio.h:52:16: note: in a call to function ‘writev’ declared with attribute ‘read_only (2, 3)’
     52 | extern ssize_t writev (int __fd, const struct iovec *__iovec, int __count)
        |                ^~~~~~
  cc1: all warnings being treated as errors

This change helps that version of GCC to understand what is going on
and suppresses this warning.

Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>

---

 net/dump.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/dump.c b/net/dump.c
index a07ba62401..c32d3bf4e6 100644
--- a/net/dump.c
+++ b/net/dump.c
@@ -86,7 +86,7 @@ static ssize_t dump_receive_iov(DumpState *s, const struct iovec *iov, int cnt)
     dumpiov[0].iov_len = sizeof(hdr);
     cnt = iov_copy(&dumpiov[1], cnt, iov, cnt, 0, caplen);
 
-    if (writev(s->fd, dumpiov, cnt + 1) != sizeof(hdr) + caplen) {
+    if (writev(s->fd, &dumpiov[0], cnt + 1) != sizeof(hdr) + caplen) {
         error_report("network dump write error - stopping dump");
         close(s->fd);
         s->fd = -1;
-- 
2.33.1