[v2,2/2] lockable: add QemuRecMutex support

Commit Message

Stefan Hajnoczi March 16, 2020, 11:09 a.m. UTC

The polymorphic locking macros don't support QemuRecMutex yet.  Add it
so that lock guards can be used with QemuRecMutex.

Convert TCG plugins functions that benefit from these macros.  Manual
qemu_rec_mutex_lock/unlock() callers are left unmodified in cases where
clarity would not improve by switching to the macros.

Signed-off-by: Stefan Hajnoczi <[e-mail]>
---
 include/qemu/lockable.h |  2 ++
 plugins/core.c          |  7 +++----
 plugins/loader.c        | 16 ++++++++--------
 3 files changed, 13 insertions(+), 12 deletions(-)

Patch

diff --git a/include/qemu/lockable.h b/include/qemu/lockable.h
index 2b52c7c1e5..44b3f4be72 100644
--- a/include/qemu/lockable.h
+++ b/include/qemu/lockable.h
@@ -50,6 +50,7 @@  qemu_make_lockable(void *x, QemuLockable *lockable)
 #define QEMU_LOCK_FUNC(x) ((QemuLockUnlockFunc *)    \
     QEMU_GENERIC(x,                                  \
                  (QemuMutex *, qemu_mutex_lock),     \
+                 (QemuRecMutex *, qemu_rec_mutex_lock), \
                  (CoMutex *, qemu_co_mutex_lock),    \
                  (QemuSpin *, qemu_spin_lock),       \
                  unknown_lock_type))
@@ -57,6 +58,7 @@  qemu_make_lockable(void *x, QemuLockable *lockable)
 #define QEMU_UNLOCK_FUNC(x) ((QemuLockUnlockFunc *)  \
     QEMU_GENERIC(x,                                  \
                  (QemuMutex *, qemu_mutex_unlock),   \
+                 (QemuRecMutex *, qemu_rec_mutex_unlock), \
                  (CoMutex *, qemu_co_mutex_unlock),  \
                  (QemuSpin *, qemu_spin_unlock),     \
                  unknown_lock_type))
diff --git a/plugins/core.c b/plugins/core.c
index ed863011ba..51bfc94787 100644
--- a/plugins/core.c
+++ b/plugins/core.c
@@ -15,6 +15,7 @@ 
 #include "qemu/error-report.h"
 #include "qemu/config-file.h"
 #include "qapi/error.h"
+#include "qemu/lockable.h"
 #include "qemu/option.h"
 #include "qemu/rcu_queue.h"
 #include "qemu/xxhash.h"
@@ -150,11 +151,11 @@  do_plugin_register_cb(qemu_plugin_id_t id, enum qemu_plugin_event ev,
 {
     struct qemu_plugin_ctx *ctx;
 
-    qemu_rec_mutex_lock(&plugin.lock);
+    QEMU_LOCK_GUARD(&plugin.lock);
     ctx = plugin_id_to_ctx_locked(id);
     /* if the plugin is on its way out, ignore this request */
     if (unlikely(ctx->uninstalling)) {
-        goto out_unlock;
+        return;
     }
     if (func) {
         struct qemu_plugin_cb *cb = ctx->callbacks[ev];
@@ -178,8 +179,6 @@  do_plugin_register_cb(qemu_plugin_id_t id, enum qemu_plugin_event ev,
     } else {
         plugin_unregister_cb__locked(ctx, ev);
     }
- out_unlock:
-    qemu_rec_mutex_unlock(&plugin.lock);
 }
 
 void plugin_register_cb(qemu_plugin_id_t id, enum qemu_plugin_event ev,
diff --git a/plugins/loader.c b/plugins/loader.c
index 15fc7e5515..685d334e1a 100644
--- a/plugins/loader.c
+++ b/plugins/loader.c
@@ -19,6 +19,7 @@ 
 #include "qemu/error-report.h"
 #include "qemu/config-file.h"
 #include "qapi/error.h"
+#include "qemu/lockable.h"
 #include "qemu/option.h"
 #include "qemu/rcu_queue.h"
 #include "qemu/qht.h"
@@ -367,15 +368,14 @@  void plugin_reset_uninstall(qemu_plugin_id_t id,
     struct qemu_plugin_reset_data *data;
     struct qemu_plugin_ctx *ctx;
 
-    qemu_rec_mutex_lock(&plugin.lock);
-    ctx = plugin_id_to_ctx_locked(id);
-    if (ctx->uninstalling || (reset && ctx->resetting)) {
-        qemu_rec_mutex_unlock(&plugin.lock);
-        return;
+    WITH_QEMU_LOCK_GUARD(&plugin.lock) {
+        ctx = plugin_id_to_ctx_locked(id);
+        if (ctx->uninstalling || (reset && ctx->resetting)) {
+            return;
+        }
+        ctx->resetting = reset;
+        ctx->uninstalling = !reset;
     }
-    ctx->resetting = reset;
-    ctx->uninstalling = !reset;
-    qemu_rec_mutex_unlock(&plugin.lock);
 
     data = g_new(struct qemu_plugin_reset_data, 1);
     data->ctx = ctx;