[PATCH v2 1/2] QIOChannelSocket: Reduce ifdefs to improve readability

[Leonardo Bras <leobras@redhat.com>]

During implementation of MSG_ZEROCOPY feature, a lot of #ifdefs were
introduced, particularly at qio_channel_socket_writev().

Rewrite some of those changes so it's easier to read.
									...
Signed-off-by: Leonardo Bras <leobras@redhat.com>
---
 io/channel-socket.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/io/channel-socket.c b/io/channel-socket.c
index dc9c165de1..ef7c7cfbac 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -554,6 +554,7 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc,
     size_t fdsize = sizeof(int) * nfds;
     struct cmsghdr *cmsg;
     int sflags = 0;
+    bool zero_copy_enabled = false;
 
     memset(control, 0, CMSG_SPACE(sizeof(int) * SOCKET_MAX_FDS));
 
@@ -581,6 +582,7 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc,
 #ifdef QEMU_MSG_ZEROCOPY
     if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) {
         sflags = MSG_ZEROCOPY;
+        zero_copy_enabled = true;
     }
 #endif
 
@@ -592,15 +594,13 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc,
             return QIO_CHANNEL_ERR_BLOCK;
         case EINTR:
             goto retry;
-#ifdef QEMU_MSG_ZEROCOPY
         case ENOBUFS:
-            if (sflags & MSG_ZEROCOPY) {
+            if (zero_copy_enabled) {
                 error_setg_errno(errp, errno,
                                  "Process can't lock enough memory for using MSG_ZEROCOPY");
                 return -1;
             }
             break;
-#endif
         }
 
         error_setg_errno(errp, errno,
-- 
2.36.1