[Qemu-devel] [RFC PATCH v5 14/14] slirp: use lock to protect the slirp_instances

[Liu Ping Fan]

From: Liu Ping Fan <pingf...@linux.vnet.ibm.com>

slirps will run on dedicated thread, and dynamically join or disjoin
this list, so need lock to protect the global list.

Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com>
---
 include/qemu/module.h |    2 ++
 slirp/slirp.c         |   20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/include/qemu/module.h b/include/qemu/module.h
index c4ccd57..2720943 100644
--- a/include/qemu/module.h
+++ b/include/qemu/module.h
@@ -22,6 +22,7 @@ static void __attribute__((constructor)) do_qemu_init_ ## 
function(void) {  \
 
 typedef enum {
     MODULE_INIT_BLOCK,
+    MODULE_INIT_SLIRP,
     MODULE_INIT_MACHINE,
     MODULE_INIT_QAPI,
     MODULE_INIT_QOM,
@@ -29,6 +30,7 @@ typedef enum {
 } module_init_type;
 
 #define block_init(function) module_init(function, MODULE_INIT_BLOCK)
+#define slirplayer_init(function) module_init(function, MODULE_INIT_SLIRP)
 #define machine_init(function) module_init(function, MODULE_INIT_MACHINE)
 #define qapi_init(function) module_init(function, MODULE_INIT_QAPI)
 #define type_init(function) module_init(function, MODULE_INIT_QOM)
diff --git a/slirp/slirp.c b/slirp/slirp.c
index 8f5cbe0..3008c7b 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -42,6 +42,7 @@ static const uint8_t zero_ethaddr[ETH_ALEN] = { 0, 0, 0, 0, 
0, 0 };
 
 u_int curtime;
 
+static QemuMutex slirp_instances_lock;
 static QTAILQ_HEAD(slirp_instances, Slirp) slirp_instances =
     QTAILQ_HEAD_INITIALIZER(slirp_instances);
 
@@ -236,14 +237,18 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
     register_savevm(NULL, "slirp", 0, 3,
                     slirp_state_save, slirp_state_load, slirp);
 
+    qemu_mutex_lock(&slirp_instances_lock);
     QTAILQ_INSERT_TAIL(&slirp_instances, slirp, entry);
+    qemu_mutex_unlock(&slirp_instances_lock);
 
     return slirp;
 }
 
 void slirp_cleanup(Slirp *slirp)
 {
+    qemu_mutex_lock(&slirp_instances_lock);
     QTAILQ_REMOVE(&slirp_instances, slirp, entry);
+    qemu_mutex_unlock(&slirp_instances_lock);
 
     unregister_savevm(NULL, "slirp", slirp);
 
@@ -262,9 +267,12 @@ void slirp_cleanup(Slirp *slirp)
 
 void slirp_update_timeout(uint32_t *timeout)
 {
+    qemu_mutex_lock(&slirp_instances_lock);
     if (!QTAILQ_EMPTY(&slirp_instances)) {
         *timeout = MIN(1000, *timeout);
     }
+    qemu_mutex_unlock(&slirp_instances_lock);
+
     curtime = qemu_get_clock_ms(rt_clock);
 }
 
@@ -1167,3 +1175,15 @@ static int slirp_state_load(QEMUFile *f, void *opaque, 
int version_id)
 
     return 0;
 }
+
+static void slirplayer_cleanup(void)
+{
+    qemu_mutex_destroy(&slirp_instances_lock);
+}
+
+static void slirplayer_bootup(void)
+{
+    qemu_mutex_init(&slirp_instances_lock);
+    atexit(&slirplayer_cleanup);
+}
+slirplayer_init(slirplayer_bootup)
-- 
1.7.4.4