hw/usb: Use lock guard macros

Use qemu LOCK_GUARD macros from "qemu/lockable.h" in
hw/usb/ccid-card-emulated.c, saves manual unlock calls.

Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200923134327.576139-1-ameynarkhede03@gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hw/usb/ccid-card-emulated.c

@@ -30,6 +30,7 @@
 #include <libcacard.h>
 
 #include "qemu/thread.h"
+#include "qemu/lockable.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
 #include "ccid.h"
@@ -244,34 +245,34 @@ static void *handle_apdu_thread(void* arg)
             card->quit_apdu_thread = 0; /* debugging */
             break;
         }
-        qemu_mutex_lock(&card->vreader_mutex);
-        while (!QSIMPLEQ_EMPTY(&card->guest_apdu_list)) {
-            event = QSIMPLEQ_FIRST(&card->guest_apdu_list);
-            assert((unsigned long)event > 1000);
-            QSIMPLEQ_REMOVE_HEAD(&card->guest_apdu_list, entry);
-            if (event->p.data.type != EMUL_GUEST_APDU) {
-                DPRINTF(card, 1, "unexpected message in handle_apdu_thread\n");
-                g_free(event);
-                continue;
-            }
-            if (card->reader == NULL) {
-                DPRINTF(card, 1, "reader is NULL\n");
+        WITH_QEMU_LOCK_GUARD(&card->vreader_mutex) {
+            while (!QSIMPLEQ_EMPTY(&card->guest_apdu_list)) {
+                event = QSIMPLEQ_FIRST(&card->guest_apdu_list);
+                assert((unsigned long)event > 1000);
+                QSIMPLEQ_REMOVE_HEAD(&card->guest_apdu_list, entry);
+                if (event->p.data.type != EMUL_GUEST_APDU) {
+                    DPRINTF(card, 1, "unexpected message in handle_apdu_thread\n");
+                    g_free(event);
+                    continue;
+                }
+                if (card->reader == NULL) {
+                    DPRINTF(card, 1, "reader is NULL\n");
+                    g_free(event);
+                    continue;
+                }
+                recv_len = sizeof(recv_data);
+                reader_status = vreader_xfr_bytes(card->reader,
+                        event->p.data.data, event->p.data.len,
+                        recv_data, &recv_len);
+                DPRINTF(card, 2, "got back apdu of length %d\n", recv_len);
+                if (reader_status == VREADER_OK) {
+                    emulated_push_response_apdu(card, recv_data, recv_len);
+                } else {
+                    emulated_push_error(card, reader_status);
+                }
                 g_free(event);
-                continue;
             }
-            recv_len = sizeof(recv_data);
-            reader_status = vreader_xfr_bytes(card->reader,
-                    event->p.data.data, event->p.data.len,
-                    recv_data, &recv_len);
-            DPRINTF(card, 2, "got back apdu of length %d\n", recv_len);
-            if (reader_status == VREADER_OK) {
-                emulated_push_response_apdu(card, recv_data, recv_len);
-            } else {
-                emulated_push_error(card, reader_status);
-            }
-            g_free(event);
         }
-        qemu_mutex_unlock(&card->vreader_mutex);
     }
     return NULL;
 }
@@ -365,7 +366,7 @@ static void card_event_handler(EventNotifier *notifier)
     EmulEvent *event, *next;
 
     event_notifier_test_and_clear(&card->notifier);
-    qemu_mutex_lock(&card->event_list_mutex);
+    QEMU_LOCK_GUARD(&card->event_list_mutex);
     QSIMPLEQ_FOREACH_SAFE(event, &card->event_list, entry, next) {
         DPRINTF(card, 2, "event %s\n", emul_event_to_string(event->p.gen.type));
         switch (event->p.gen.type) {
@@ -398,7 +399,6 @@ static void card_event_handler(EventNotifier *notifier)
         g_free(event);
     }
     QSIMPLEQ_INIT(&card->event_list);
-    qemu_mutex_unlock(&card->event_list_mutex);
 }
 
 static int init_event_notifier(EmulatedState *card, Error **errp)