diff mbox series

[v4,1/4] QIOChannelSocket: Introduce assert and reduce ifdefs to improve readability

Message ID 20220620053944.257547-2-leobras@redhat.com (mailing list archive)
State New, archived
Headers show
Series MSG_ZEROCOPY fixes & improvements | expand

Commit Message

Leonardo Bras June 20, 2022, 5:39 a.m. UTC 
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.

Also, introduce an assert to help detect incorrect zero-copy usage is when
it's disabled on build.

Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---
 io/channel-socket.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

Comments

Juan Quintela June 20, 2022, 8:47 a.m. UTC | #1 
Leonardo Bras <leobras@redhat.com> wrote:
> 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.
>
> Also, introduce an assert to help detect incorrect zero-copy usage is when
> it's disabled on build.
>
> Signed-off-by: Leonardo Bras <leobras@redhat.com>
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>
Peter Xu June 20, 2022, 3:27 p.m. UTC | #2 
On Mon, Jun 20, 2022 at 02:39:42AM -0300, Leonardo Bras wrote:
> 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.
> 
> Also, introduce an assert to help detect incorrect zero-copy usage is when
> it's disabled on build.
> 
> Signed-off-by: Leonardo Bras <leobras@redhat.com>
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>
diff mbox series

Patch

diff --git a/io/channel-socket.c b/io/channel-socket.c
index dc9c165de1..dac9e60c20 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -578,11 +578,17 @@  static ssize_t qio_channel_socket_writev(QIOChannel *ioc,
         memcpy(CMSG_DATA(cmsg), fds, fdsize);
     }
 
-#ifdef QEMU_MSG_ZEROCOPY
     if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) {
+#ifdef QEMU_MSG_ZEROCOPY
         sflags = MSG_ZEROCOPY;
-    }
+#else
+        /*
+         * We expect QIOChannel class entry point to have
+         * blocked this code path already
+         */
+        g_assert_unreachable();
 #endif
+    }
 
  retry:
     ret = sendmsg(sioc->fd, &msg, sflags);
@@ -592,15 +598,13 @@  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 (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) {
                 error_setg_errno(errp, errno,
                                  "Process can't lock enough memory for using MSG_ZEROCOPY");
                 return -1;
             }
             break;
-#endif
         }
 
         error_setg_errno(errp, errno,