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[PATCH 2/6] libvhost-user: Use slave_mutex in all slave messages
From: |
Vivek Goyal |
Subject: |
[PATCH 2/6] libvhost-user: Use slave_mutex in all slave messages |
Date: |
Mon, 25 Jan 2021 13:01:11 -0500 |
dev->slave_mutex needs to be taken when sending messages on slave_fd.
Currently _vu_queue_notify() does not do that.
Introduce a helper vu_message_slave_send_receive() which sends as well
as receive response. Use this helper in all the paths which send
message on slave_fd channel.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
subprojects/libvhost-user/libvhost-user.c | 50 ++++++++++++-----------
1 file changed, 27 insertions(+), 23 deletions(-)
diff --git a/subprojects/libvhost-user/libvhost-user.c
b/subprojects/libvhost-user/libvhost-user.c
index 4cf4aef63d..7a56c56dc8 100644
--- a/subprojects/libvhost-user/libvhost-user.c
+++ b/subprojects/libvhost-user/libvhost-user.c
@@ -403,7 +403,7 @@ vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
* Processes a reply on the slave channel.
* Entered with slave_mutex held and releases it before exit.
* Returns true on success.
- * *payload is written on success
+ * *payload is written on success, if payload is not NULL.
*/
static bool
vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg,
@@ -427,7 +427,9 @@ vu_process_message_reply(VuDev *dev, const VhostUserMsg
*vmsg,
goto out;
}
- *payload = msg_reply.payload.u64;
+ if (payload) {
+ *payload = msg_reply.payload.u64;
+ }
result = true;
out:
@@ -435,6 +437,25 @@ out:
return result;
}
+/* Returns true on success, false otherwise */
+static bool
+vu_message_slave_send_receive(VuDev *dev, VhostUserMsg *vmsg, uint64_t
*payload)
+{
+ pthread_mutex_lock(&dev->slave_mutex);
+ if (!vu_message_write(dev, dev->slave_fd, vmsg)) {
+ pthread_mutex_unlock(&dev->slave_mutex);
+ return false;
+ }
+
+ if ((vmsg->flags & VHOST_USER_NEED_REPLY_MASK) == 0) {
+ pthread_mutex_unlock(&dev->slave_mutex);
+ return true;
+ }
+
+ /* Also unlocks the slave_mutex */
+ return vu_process_message_reply(dev, vmsg, payload);
+}
+
/* Kick the log_call_fd if required. */
static void
vu_log_kick(VuDev *dev)
@@ -1340,16 +1361,8 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq,
int fd,
return false;
}
- pthread_mutex_lock(&dev->slave_mutex);
- if (!vu_message_write(dev, dev->slave_fd, &vmsg)) {
- pthread_mutex_unlock(&dev->slave_mutex);
- return false;
- }
-
- /* Also unlocks the slave_mutex */
- res = vu_process_message_reply(dev, &vmsg, &payload);
+ res = vu_message_slave_send_receive(dev, &vmsg, &payload);
res = res && (payload == 0);
-
return res;
}
@@ -2395,10 +2408,7 @@ static void _vu_queue_notify(VuDev *dev, VuVirtq *vq,
bool sync)
vmsg.flags |= VHOST_USER_NEED_REPLY_MASK;
}
- vu_message_write(dev, dev->slave_fd, &vmsg);
- if (ack) {
- vu_message_read_default(dev, dev->slave_fd, &vmsg);
- }
+ vu_message_slave_send_receive(dev, &vmsg, NULL);
return;
}
@@ -2942,17 +2952,11 @@ int64_t vu_fs_cache_request(VuDev *dev,
VhostUserSlaveRequest req, int fd,
return -EINVAL;
}
- pthread_mutex_lock(&dev->slave_mutex);
- if (!vu_message_write(dev, dev->slave_fd, &vmsg)) {
- pthread_mutex_unlock(&dev->slave_mutex);
- return -EIO;
- }
-
- /* Also unlocks the slave_mutex */
- res = vu_process_message_reply(dev, &vmsg, &payload);
+ res = vu_message_slave_send_receive(dev, &vmsg, &payload);
if (!res) {
return -EIO;
}
+
/*
* Payload is delivered as uint64_t but is actually signed for
* errors.
--
2.25.4