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, 5 insertions, 5 deletions

diff --git a/accel/accel-blocker.c b/accel/accel-blocker.c
index 1e7f423462..e083f24aa8 100644
--- a/accel/accel-blocker.c
+++ b/accel/accel-blocker.c
@@ -41,7 +41,7 @@ void accel_blocker_init(void)
 
 void accel_ioctl_begin(void)
 {
-    if (likely(qemu_mutex_iothread_locked())) {
+    if (likely(bql_locked())) {
         return;
     }
 
@@ -51,7 +51,7 @@ void accel_ioctl_begin(void)
 
 void accel_ioctl_end(void)
 {
-    if (likely(qemu_mutex_iothread_locked())) {
+    if (likely(bql_locked())) {
         return;
     }
 
@@ -62,7 +62,7 @@ void accel_ioctl_end(void)
 
 void accel_cpu_ioctl_begin(CPUState *cpu)
 {
-    if (unlikely(qemu_mutex_iothread_locked())) {
+    if (unlikely(bql_locked())) {
         return;
     }
 
@@ -72,7 +72,7 @@ void accel_cpu_ioctl_begin(CPUState *cpu)
 
 void accel_cpu_ioctl_end(CPUState *cpu)
 {
-    if (unlikely(qemu_mutex_iothread_locked())) {
+    if (unlikely(bql_locked())) {
         return;
     }
 
@@ -105,7 +105,7 @@ void accel_ioctl_inhibit_begin(void)
      * We allow to inhibit only when holding the BQL, so we can identify
      * when an inhibitor wants to issue an ioctl easily.
      */
-    g_assert(qemu_mutex_iothread_locked());
+    g_assert(bql_locked());
 
     /* Block further invocations of the ioctls outside the BQL.  */
     CPU_FOREACH(cpu) {