[Qemu-devel] [RFC v1 1/3] bouce buffer has fine grain lock

[Liu Ping Fan <qemulist@gmail.com>]

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

Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
 exec.c |   21 +++++++++++++--------
 1 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/exec.c b/exec.c
index 73d5242..fe84718 100644
--- a/exec.c
+++ b/exec.c
@@ -3296,6 +3296,15 @@ void address_space_destroy_dispatch(AddressSpace *as)
     as->dispatch = NULL;
 }
 
+typedef struct {
+    QemuMutex lock;
+    void *buffer;
+    target_phys_addr_t addr;
+    target_phys_addr_t len;
+} BounceBuffer;
+
+static BounceBuffer bounce;
+
 static void memory_map_init(void)
 {
     system_memory = g_malloc(sizeof(*system_memory));
@@ -3308,6 +3317,8 @@ static void memory_map_init(void)
     address_space_init(&address_space_io, system_io);
     address_space_io.name = "I/O";
 
+    qemu_mutex_init(&bounce.lock);
+
     memory_listener_register(&core_memory_listener, &address_space_memory);
     memory_listener_register(&io_memory_listener, &address_space_io);
     memory_listener_register(&tcg_memory_listener, &address_space_memory);
@@ -3671,14 +3682,6 @@ void cpu_physical_memory_write_rom(target_phys_addr_t addr,
     }
 }
 
-typedef struct {
-    void *buffer;
-    target_phys_addr_t addr;
-    target_phys_addr_t len;
-} BounceBuffer;
-
-static BounceBuffer bounce;
-
 typedef struct MapClient {
     void *opaque;
     void (*callback)(void *opaque);
@@ -3747,6 +3750,7 @@ void *address_space_map(AddressSpace *as,
         section = &mr_obj;
 
         if (!(memory_region_is_ram(section->mr) && !section->readonly)) {
+            qemu_mutex_lock(&bounce.lock);
             if (todo || bounce.buffer) {
                 break;
             }
@@ -3807,6 +3811,7 @@ void address_space_unmap(AddressSpace *as, void *buffer, target_phys_addr_t len,
     }
     qemu_vfree(bounce.buffer);
     bounce.buffer = NULL;
+    qemu_mutex_unlock(&bounce.lock);
     cpu_notify_map_clients();
 }
 
-- 
1.7.4.4