[Qemu-devel] [PATCH v3 3/7] net: introduce lock to protect NetQueue

[Liu Ping Fan]

NetQueue will be accessed by nc and its peers at the same time,
need lock to protect it.

Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com>
---
 include/net/net.h |  1 +
 net/queue.c       | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/include/net/net.h b/include/net/net.h
index 43d85a1..2f72b26 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -5,6 +5,7 @@
 #include "qemu-common.h"
 #include "qapi/qmp/qdict.h"
 #include "qemu/option.h"
+#include "qemu/thread.h"
 #include "net/queue.h"
 #include "migration/vmstate.h"
 #include "qapi-types.h"
diff --git a/net/queue.c b/net/queue.c
index d508b7a..26399a1 100644
--- a/net/queue.c
+++ b/net/queue.c
@@ -56,6 +56,7 @@ struct NetQueue {
     uint32_t nq_maxlen;
     uint32_t nq_count;
 
+    QemuMutex lock;
     QTAILQ_HEAD(packets, NetPacket) packets;
 
     unsigned delivering : 1;
@@ -88,6 +89,7 @@ NetQueue *qemu_new_net_queue(NetClientState *nc)
     queue->nq_maxlen = 10000;
     queue->nq_count = 0;
 
+    qemu_mutex_init(&queue->lock);
     QTAILQ_INIT(&queue->packets);
 
     queue->delivering = 0;
@@ -116,7 +118,9 @@ static void qemu_net_queue_append(NetQueue *queue,
 {
     NetPacket *packet;
 
+    qemu_mutex_lock(&queue->lock);
     if (queue->nq_count >= queue->nq_maxlen && !sent_cb) {
+        qemu_mutex_unlock(&queue->lock);
         return; /* drop if queue full and no callback */
     }
     packet = g_malloc(sizeof(NetPacket) + size);
@@ -128,6 +132,7 @@ static void qemu_net_queue_append(NetQueue *queue,
 
     queue->nq_count++;
     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
+    qemu_mutex_unlock(&queue->lock);
 }
 
 static void qemu_net_queue_append_iov(NetQueue *queue,
@@ -141,7 +146,9 @@ static void qemu_net_queue_append_iov(NetQueue *queue,
     size_t max_len = 0;
     int i;
 
+    qemu_mutex_lock(&queue->lock);
     if (queue->nq_count >= queue->nq_maxlen && !sent_cb) {
+        qemu_mutex_unlock(&queue->lock);
         return; /* drop if queue full and no callback */
     }
     for (i = 0; i < iovcnt; i++) {
@@ -163,6 +170,7 @@ static void qemu_net_queue_append_iov(NetQueue *queue,
 
     queue->nq_count++;
     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
+    qemu_mutex_unlock(&queue->lock);
 }
 
 static ssize_t qemu_net_queue_deliver(NetQueue *queue,
@@ -273,6 +281,7 @@ void qemu_net_queue_purge(NetQueue *queue, NetClientState 
*from)
 {
     NetPacket *packet, *next;
 
+    qemu_mutex_lock(&queue->lock);
     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
         if (packet->sender == from) {
             QTAILQ_REMOVE(&queue->packets, packet, entry);
@@ -280,10 +289,12 @@ void qemu_net_queue_purge(NetQueue *queue, NetClientState 
*from)
             g_free(packet);
         }
     }
+    qemu_mutex_unlock(&queue->lock);
 }
 
 bool qemu_net_queue_flush(NetQueue *queue)
 {
+    qemu_mutex_lock(&queue->lock);
     while (!QTAILQ_EMPTY(&queue->packets)) {
         NetPacket *packet;
         int ret;
@@ -300,6 +311,7 @@ bool qemu_net_queue_flush(NetQueue *queue)
         if (ret == 0) {
             queue->nq_count++;
             QTAILQ_INSERT_HEAD(&queue->packets, packet, entry);
+            qemu_mutex_unlock(&queue->lock);
             return false;
         }
 
@@ -309,5 +321,6 @@ bool qemu_net_queue_flush(NetQueue *queue)
 
         g_free(packet);
     }
+    qemu_mutex_unlock(&queue->lock);
     return true;
 }
-- 
1.8.1.4