block: split BlockAcctStats creation and setup

block_acct_destroy is called unconditionally in blk_delete, but there is
no BlockAcctStats function that is called unconditionally in blk_new.
Split block_acct_init in two, so that it will be possible to create a
QemuMutex in block_acct_init and destroy it in block_acct_cleanup.

Cc: Alberto Garcia <berto@igalia.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170605123908.18777-19-pbonzini@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NFam Zheng <famz@redhat.com>

block/accounting.c

@@ -32,17 +32,20 @@
 static QEMUClockType clock_type = QEMU_CLOCK_REALTIME;
 static const int qtest_latency_ns = NANOSECONDS_PER_SECOND / 1000;
 
-void block_acct_init(BlockAcctStats *stats, bool account_invalid,
-                     bool account_failed)
+void block_acct_init(BlockAcctStats *stats)
 {
-    stats->account_invalid = account_invalid;
-    stats->account_failed = account_failed;
-
     if (qtest_enabled()) {
         clock_type = QEMU_CLOCK_VIRTUAL;
     }
 }
 
+void block_acct_setup(BlockAcctStats *stats, bool account_invalid,
+                      bool account_failed)
+{
+    stats->account_invalid = account_invalid;
+    stats->account_failed = account_failed;
+}
+
 void block_acct_cleanup(BlockAcctStats *stats)
 {
     BlockAcctTimedStats *s, *next;

block/block-backend.c

@@ -219,6 +219,7 @@ BlockBackend *blk_new(uint64_t perm, uint64_t shared_perm)
     qemu_co_mutex_init(&blk->public.throttled_reqs_lock);
     qemu_co_queue_init(&blk->public.throttled_reqs[0]);
     qemu_co_queue_init(&blk->public.throttled_reqs[1]);
+    block_acct_init(&blk->stats);
 
     notifier_list_init(&blk->remove_bs_notifiers);
     notifier_list_init(&blk->insert_bs_notifiers);

blockdev.c

@@ -595,7 +595,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
             autostart = 0;
         }
 
-        block_acct_init(blk_get_stats(blk), account_invalid, account_failed);
+        block_acct_setup(blk_get_stats(blk), account_invalid, account_failed);
 
         if (!parse_stats_intervals(blk_get_stats(blk), interval_list, errp)) {
             blk_unref(blk);

include/block/accounting.h

@@ -61,7 +61,8 @@ typedef struct BlockAcctCookie {
     enum BlockAcctType type;
 } BlockAcctCookie;
 
-void block_acct_init(BlockAcctStats *stats, bool account_invalid,
+void block_acct_init(BlockAcctStats *stats);
+void block_acct_setup(BlockAcctStats *stats, bool account_invalid,
                      bool account_failed);
 void block_acct_cleanup(BlockAcctStats *stats);
 void block_acct_add_interval(BlockAcctStats *stats, unsigned interval_length);