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[Qemu-devel] [PATCH v4 4/5] exec: Notify cpu_register_map_client caller
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH v4 4/5] exec: Notify cpu_register_map_client caller if the bounce buffer is available |
Date: |
Mon, 16 Mar 2015 17:03:36 +0800 |
The caller's workflow is like
if (!address_space_map()) {
...
cpu_register_map_client();
}
If bounce buffer became available after address_space_map() but before
cpu_register_map_client(), the caller could miss it and has to wait for the
next bounce buffer notify, which may never happen in the worse case.
Just notify the list in cpu_register_map_client().
Signed-off-by: Fam Zheng <address@hidden>
---
exec.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
diff --git a/exec.c b/exec.c
index 9f6c4f8..0fa7487 100644
--- a/exec.c
+++ b/exec.c
@@ -2489,6 +2489,18 @@ QemuMutex map_client_list_lock;
static QLIST_HEAD(map_client_list, MapClient) map_client_list
= QLIST_HEAD_INITIALIZER(map_client_list);
+static void cpu_unregister_map_client(void *_client);
+static void cpu_notify_map_clients_locked(void)
+{
+ MapClient *client;
+
+ while (!QLIST_EMPTY(&map_client_list)) {
+ client = QLIST_FIRST(&map_client_list);
+ client->callback(client->opaque);
+ cpu_unregister_map_client(client);
+ }
+}
+
void *cpu_register_map_client(void *opaque, void (*callback)(void *opaque))
{
MapClient *client = g_malloc(sizeof(*client));
@@ -2497,6 +2509,9 @@ 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);
+ if (!atomic_read(&bounce.in_use)) {
+ cpu_notify_map_clients_locked();
+ }
qemu_mutex_unlock(&map_client_list_lock);
return client;
}
@@ -2521,14 +2536,8 @@ static void cpu_unregister_map_client(void *_client)
static void cpu_notify_map_clients(void)
{
- MapClient *client;
-
qemu_mutex_lock(&map_client_list_lock);
- while (!QLIST_EMPTY(&map_client_list)) {
- client = QLIST_FIRST(&map_client_list);
- client->callback(client->opaque);
- cpu_unregister_map_client(client);
- }
+ cpu_notify_map_clients_locked();
qemu_mutex_unlock(&map_client_list_lock);
}
--
1.9.3
- [Qemu-devel] [PATCH v4 0/5] exec: Make bounce buffer thread safe, Fam Zheng, 2015/03/16
- [Qemu-devel] [PATCH v4 3/5] exec: Protect map_client_list with mutex, Fam Zheng, 2015/03/16
- [Qemu-devel] [PATCH v4 1/5] exec: Atomic access to bounce buffer, Fam Zheng, 2015/03/16
- [Qemu-devel] [PATCH v4 2/5] linux-user, bsd-user: Remove two calls to cpu_exec_init_all, Fam Zheng, 2015/03/16
- [Qemu-devel] [PATCH v4 4/5] exec: Notify cpu_register_map_client caller if the bounce buffer is available,
Fam Zheng <=
- [Qemu-devel] [PATCH v4 5/5] dma-helpers: Fix race condition of continue_after_map_failure and dma_aio_cancel, Fam Zheng, 2015/03/16