Change map_client_list to QSLIST which supports atomic operations.
There are two access points to map_client_list. One is
cpu_register_map_client, the other is cpu_notify_map_clients called
after releasing the global bounce buffer in address_space_unmap. Each
is now converted to a single atomic operation.
Signed-off-by: Fam Zheng <f...@redhat.com>
---
exec.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)
diff --git a/exec.c b/exec.c
index 8d4e134..93ccd5a 100644
--- a/exec.c
+++ b/exec.c
@@ -2489,11 +2489,11 @@ static BounceBuffer bounce;
typedef struct MapClient {
void *opaque;
void (*callback)(void *opaque);
- QLIST_ENTRY(MapClient) link;
+ QSLIST_ENTRY(MapClient) link;
} MapClient;
-static QLIST_HEAD(map_client_list, MapClient) map_client_list
- = QLIST_HEAD_INITIALIZER(map_client_list);
+static QSLIST_HEAD(map_client_list, MapClient) map_client_list
+ = QSLIST_HEAD_INITIALIZER(map_client_list);
void *cpu_register_map_client(void *opaque, void (*callback)(void *opaque))
{
@@ -2501,26 +2501,23 @@ void *cpu_register_map_client(void *opaque, void
(*callback)(void *opaque))
client->opaque = opaque;
client->callback = callback;
- QLIST_INSERT_HEAD(&map_client_list, client, link);
+ QSLIST_INSERT_HEAD_ATOMIC(&map_client_list, client, link);
return client;
}
-static void cpu_unregister_map_client(void *_client)
-{
- MapClient *client = (MapClient *)_client;
-
- QLIST_REMOVE(client, link);
- g_free(client);
-}
-
static void cpu_notify_map_clients(void)
{
MapClient *client;
+ QSLIST_HEAD(, MapClient) mclist;
- while (!QLIST_EMPTY(&map_client_list)) {
- client = QLIST_FIRST(&map_client_list);
+ /* Only the bounce buffer owner thread could possibly call this, but we
+ * should also coordinate with cpu_register_map_client. */
+ QSLIST_MOVE_ATOMIC(&mclist, &map_client_list);
+ while (!QSLIST_EMPTY(&mclist)) {
+ client = QSLIST_FIRST(&mclist);
client->callback(client->opaque);
- cpu_unregister_map_client(client);
+ QSLIST_REMOVE_HEAD(&mclist, link);
+ g_free(client);
}
}
--
1.9.3
