system/cpus: rename qemu_mutex_lock_iothread() to bql_lock()

The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonly
referred to as the BQL in discussions and some code comments. The
locking APIs, however, are called qemu_mutex_lock_iothread() and
qemu_mutex_unlock_iothread().

The "iothread" name is historic and comes from when the main thread was
split into into KVM vcpu threads and the "iothread" (now called the main
loop thread). I have contributed to the confusion myself by introducing
a separate --object iothread, a separate concept unrelated to the BQL.

The "iothread" name is no longer appropriate for the BQL. Rename the
locking APIs to:
- void bql_lock(void)
- void bql_unlock(void)
- bool bql_locked(void)

There are more APIs with "iothread" in their names. Subsequent patches
will rename them. There are also comments and documentation that will be
updated in later patches.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Fabiano Rosas <farosas@suse.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/hw/net/xen_nic.c b/hw/net/xen_nic.c
index 1e2b3baeb1..453fdb9819 100644
--- a/hw/net/xen_nic.c
+++ b/hw/net/xen_nic.c
@@ -133,7 +133,7 @@ static bool net_tx_packets(struct XenNetDev *netdev)
     void *page;
     void *tmpbuf = NULL;
 
-    assert(qemu_mutex_iothread_locked());
+    assert(bql_locked());
 
     for (;;) {
         rc = netdev->tx_ring.req_cons;
@@ -260,7 +260,7 @@ static ssize_t net_rx_packet(NetClientState *nc, const uint8_t *buf, size_t size
     RING_IDX rc, rp;
     void *page;
 
-    assert(qemu_mutex_iothread_locked());
+    assert(bql_locked());
 
     if (xen_device_backend_get_state(&netdev->xendev) != XenbusStateConnected) {
         return -1;
@@ -354,7 +354,7 @@ static bool xen_netdev_connect(XenDevice *xendev, Error **errp)
     XenNetDev *netdev = XEN_NET_DEVICE(xendev);
     unsigned int port, rx_copy;
 
-    assert(qemu_mutex_iothread_locked());
+    assert(bql_locked());
 
     if (xen_device_frontend_scanf(xendev, "tx-ring-ref", "%u",
                                   &netdev->tx_ring_ref) != 1) {
@@ -425,7 +425,7 @@ static void xen_netdev_disconnect(XenDevice *xendev, Error **errp)
 
     trace_xen_netdev_disconnect(netdev->dev);
 
-    assert(qemu_mutex_iothread_locked());
+    assert(bql_locked());
 
     netdev->tx_ring.sring = NULL;
     netdev->rx_ring.sring = NULL;