block: make accounting thread-safe

I'm not trying too hard yet.  Later, with multiqueue support,
this may cause mutex contention or cacheline bouncing.

Cc: Alberto Garcia <berto@igalia.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170605123908.18777-20-pbonzini@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Fam Zheng <famz@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/include/block/accounting.h b/include/block/accounting.h
index 55cb06fdb6..b833d26d6c 100644
--- a/include/block/accounting.h
+++ b/include/block/accounting.h
@@ -26,8 +26,10 @@
 #define BLOCK_ACCOUNTING_H
 
 #include "qemu/timed-average.h"
+#include "qemu/thread.h"
 
 typedef struct BlockAcctTimedStats BlockAcctTimedStats;
+typedef struct BlockAcctStats BlockAcctStats;
 
 enum BlockAcctType {
     BLOCK_ACCT_READ,
@@ -37,12 +39,14 @@ enum BlockAcctType {
 };
 
 struct BlockAcctTimedStats {
+    BlockAcctStats *stats;
     TimedAverage latency[BLOCK_MAX_IOTYPE];
     unsigned interval_length; /* in seconds */
     QSLIST_ENTRY(BlockAcctTimedStats) entries;
 };
 
-typedef struct BlockAcctStats {
+struct BlockAcctStats {
+    QemuMutex lock;
     uint64_t nr_bytes[BLOCK_MAX_IOTYPE];
     uint64_t nr_ops[BLOCK_MAX_IOTYPE];
     uint64_t invalid_ops[BLOCK_MAX_IOTYPE];
@@ -53,7 +57,7 @@ typedef struct BlockAcctStats {
     QSLIST_HEAD(, BlockAcctTimedStats) intervals;
     bool account_invalid;
     bool account_failed;
-} BlockAcctStats;
+};
 
 typedef struct BlockAcctCookie {
     int64_t bytes;