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, 9 insertions, 9 deletions

diff --git a/memory_ldst.c.inc b/memory_ldst.c.inc
index 84b868f294..0e6f3940a9 100644
--- a/memory_ldst.c.inc
+++ b/memory_ldst.c.inc
@@ -61,7 +61,7 @@ static inline uint32_t glue(address_space_ldl_internal, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
     return val;
@@ -130,7 +130,7 @@ static inline uint64_t glue(address_space_ldq_internal, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
     return val;
@@ -186,7 +186,7 @@ uint8_t glue(address_space_ldub, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
     return val;
@@ -234,7 +234,7 @@ static inline uint16_t glue(address_space_lduw_internal, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
     return val;
@@ -295,7 +295,7 @@ void glue(address_space_stl_notdirty, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
 }
@@ -339,7 +339,7 @@ static inline void glue(address_space_stl_internal, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
 }
@@ -391,7 +391,7 @@ void glue(address_space_stb, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
 }
@@ -435,7 +435,7 @@ static inline void glue(address_space_stw_internal, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
 }
@@ -499,7 +499,7 @@ static void glue(address_space_stq_internal, SUFFIX)(ARG1_DECL,
         *result = r;
     }
     if (release_lock) {
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
     RCU_READ_UNLOCK();
 }