Re: [Qemu-devel] [PATCH v11 04/12] net: merge qemu_deliver_packet and qemu_deliver_packet_iov

[Yang Hongyang]

On 09/22/2015 04:14 PM, Jason Wang wrote:

On 09/22/2015 03:44 PM, Yang Hongyang wrote:

Hi Jason,

   Thanks for the review,

On 09/22/2015 03:30 PM, Jason Wang wrote:

On 09/16/2015 08:16 PM, Yang Hongyang wrote:

qemu_deliver_packet_iov already have the compat delivery, we
can drop qemu_deliver_packet.

Signed-off-by: Yang Hongyang <yan...@cn.fujitsu.com>
---
   include/net/net.h |  5 -----
   net/net.c         | 40 +++++++---------------------------------
   net/queue.c       |  6 +++++-
   3 files changed, 12 insertions(+), 39 deletions(-)

diff --git a/include/net/net.h b/include/net/net.h
index 36e5fab..7af3e15 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -152,11 +152,6 @@ void qemu_check_nic_model(NICInfo *nd, const
char *model);
   int qemu_find_nic_model(NICInfo *nd, const char * const *models,
                           const char *default_model);

-ssize_t qemu_deliver_packet(NetClientState *sender,
-                            unsigned flags,
-                            const uint8_t *data,
-                            size_t size,
-                            void *opaque);
   ssize_t qemu_deliver_packet_iov(NetClientState *sender,
                               unsigned flags,
                               const struct iovec *iov,
diff --git a/net/net.c b/net/net.c
index ad37419..ca35b27 100644
--- a/net/net.c
+++ b/net/net.c
@@ -597,36 +597,6 @@ static ssize_t filter_receive(NetClientState
*nc, NetFilterChain chain,
       return filter_receive_iov(nc, chain, sender, flags, &iov, 1,
sent_cb);
   }

-ssize_t qemu_deliver_packet(NetClientState *sender,
-                            unsigned flags,
-                            const uint8_t *data,
-                            size_t size,
-                            void *opaque)
-{
-    NetClientState *nc = opaque;
-    ssize_t ret;
-
-    if (nc->link_down) {
-        return size;
-    }
-
-    if (nc->receive_disabled) {
-        return 0;
-    }
-
-    if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) {
-        ret = nc->info->receive_raw(nc, data, size);
-    } else {
-        ret = nc->info->receive(nc, data, size);
-    }
-
-    if (ret == 0) {
-        nc->receive_disabled = 1;
-    }
-
-    return ret;
-}
-
   void qemu_purge_queued_packets(NetClientState *nc)
   {
       if (!nc->peer) {
@@ -717,14 +687,18 @@ ssize_t qemu_send_packet_raw(NetClientState
*nc, const uint8_t *buf, int size)
   }

   static ssize_t nc_sendv_compat(NetClientState *nc, const struct
iovec *iov,
-                               int iovcnt)
+                               int iovcnt, unsigned flags)
   {
       uint8_t buffer[NET_BUFSIZE];
       size_t offset;

       offset = iov_to_buf(iov, iovcnt, 0, buffer, sizeof(buffer));

-    return nc->info->receive(nc, buffer, offset);
+    if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) {
+        return nc->info->receive_raw(nc, buffer, offset);
+    } else {
+        return nc->info->receive(nc, buffer, offset);
+    }

Then for net clients that doesn't support receive_iov, an extra memcpy
is introduced. This seems unnecessary. And this patch looks independent,
so please drop this patch from the series (This can also help to reduce
the iteration). I think we may need this after all net clients support
receive_iov().

This patch is required by the next patch which introduce a
+/* Returns:
+ *   >0 - success
+ *    0 - queue packet for future redelivery
+ *   <0 - failure (discard packet)
+ */
+typedef ssize_t (NetQueueDeliverFunc)(NetClientState *sender,
+                                      unsigned flags,
+                                      const struct iovec *iov,
+                                      int iovcnt,
+                                      void *opaque);

If we drop this patch, we will need to introduce 2 deliver func, which
seems not clean and simple.

Then you can probably skip the iov_to_buf() if iov_cnt is one in the
above code?

Seems like a good idea to avoid the extra memcpy, thank you! BTW,
can I do this on top of the series if there's no other comments?
so that the first 10 patch can be merged as is. if not, I will send another
version v12 to fix this.

   }

   ssize_t qemu_deliver_packet_iov(NetClientState *sender,
@@ -747,7 +721,7 @@ ssize_t qemu_deliver_packet_iov(NetClientState
*sender,
       if (nc->info->receive_iov) {
           ret = nc->info->receive_iov(nc, iov, iovcnt);
       } else {
-        ret = nc_sendv_compat(nc, iov, iovcnt);
+        ret = nc_sendv_compat(nc, iov, iovcnt, flags);
       }

       if (ret == 0) {
diff --git a/net/queue.c b/net/queue.c
index ebbe2bb..cf8db3a 100644
--- a/net/queue.c
+++ b/net/queue.c
@@ -152,9 +152,13 @@ static ssize_t qemu_net_queue_deliver(NetQueue
*queue,
                                         size_t size)
   {
       ssize_t ret = -1;
+    struct iovec iov = {
+        .iov_base = (void *)data,
+        .iov_len = size
+    };

       queue->delivering = 1;
-    ret = qemu_deliver_packet(sender, flags, data, size,
queue->opaque);
+    ret = qemu_deliver_packet_iov(sender, flags, &iov, 1,
queue->opaque);
       queue->delivering = 0;

       return ret;

.

.

--
Thanks,
Yang.