block: Move BlockAcctStats into BlockBackend

As the comment above bdrv_get_stats() says, BlockAcctStats is something
which belongs to the device instead of each BlockDriverState. This patch
therefore moves it into the BlockBackend.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

@@ -4153,14 +4153,3 @@ void bdrv_refresh_filename(BlockDriverState *bs)
         QDECREF(json);
     }
 }
-
-/* This accessor function purpose is to allow the device models to access the
- * BlockAcctStats structure embedded inside a BlockDriverState without being
- * aware of the BlockDriverState structure layout.
- * It will go away when the BlockAcctStats structure will be moved inside
- * the device models.
- */
-BlockAcctStats *bdrv_get_stats(BlockDriverState *bs)
-{
-    return &bs->stats;
-}

block/block-backend.c

@@ -34,6 +34,9 @@ struct BlockBackend {
 
     /* the block size for which the guest device expects atomicity */
     int guest_block_size;
+
+    /* I/O stats (display with "info blockstats"). */
+    BlockAcctStats stats;
 };
 
 typedef struct BlockBackendAIOCB {
@@ -892,7 +895,7 @@ void blk_io_unplug(BlockBackend *blk)
 
 BlockAcctStats *blk_get_stats(BlockBackend *blk)
 {
-    return bdrv_get_stats(blk->bs);
+    return &blk->stats;
 }
 
 void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,

block/io.c

@@ -23,6 +23,7 @@
  */
 
 #include "trace.h"
+#include "sysemu/block-backend.h"
 #include "block/blockjob.h"
 #include "block/block_int.h"
 #include "block/throttle-groups.h"
@@ -1905,7 +1906,10 @@ static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs,
         }
     }
 
-    block_acct_merge_done(&bs->stats, BLOCK_ACCT_WRITE, num_reqs - outidx - 1);
+    if (bs->blk) {
+        block_acct_merge_done(blk_get_stats(bs->blk), BLOCK_ACCT_WRITE,
+                              num_reqs - outidx - 1);
+    }
 
     return outidx + 1;
 }

block/qapi.c

@@ -344,16 +344,20 @@ static BlockStats *bdrv_query_stats(const BlockDriverState *bs,
     }
 
     s->stats = g_malloc0(sizeof(*s->stats));
-    s->stats->rd_bytes = bs->stats.nr_bytes[BLOCK_ACCT_READ];
-    s->stats->wr_bytes = bs->stats.nr_bytes[BLOCK_ACCT_WRITE];
-    s->stats->rd_operations = bs->stats.nr_ops[BLOCK_ACCT_READ];
-    s->stats->wr_operations = bs->stats.nr_ops[BLOCK_ACCT_WRITE];
-    s->stats->rd_merged = bs->stats.merged[BLOCK_ACCT_READ];
-    s->stats->wr_merged = bs->stats.merged[BLOCK_ACCT_WRITE];
-    s->stats->flush_operations = bs->stats.nr_ops[BLOCK_ACCT_FLUSH];
-    s->stats->wr_total_time_ns = bs->stats.total_time_ns[BLOCK_ACCT_WRITE];
-    s->stats->rd_total_time_ns = bs->stats.total_time_ns[BLOCK_ACCT_READ];
-    s->stats->flush_total_time_ns = bs->stats.total_time_ns[BLOCK_ACCT_FLUSH];
+    if (bs->blk) {
+        BlockAcctStats *stats = blk_get_stats(bs->blk);
+
+        s->stats->rd_bytes = stats->nr_bytes[BLOCK_ACCT_READ];
+        s->stats->wr_bytes = stats->nr_bytes[BLOCK_ACCT_WRITE];
+        s->stats->rd_operations = stats->nr_ops[BLOCK_ACCT_READ];
+        s->stats->wr_operations = stats->nr_ops[BLOCK_ACCT_WRITE];
+        s->stats->rd_merged = stats->merged[BLOCK_ACCT_READ];
+        s->stats->wr_merged = stats->merged[BLOCK_ACCT_WRITE];
+        s->stats->flush_operations = stats->nr_ops[BLOCK_ACCT_FLUSH];
+        s->stats->wr_total_time_ns = stats->total_time_ns[BLOCK_ACCT_WRITE];
+        s->stats->rd_total_time_ns = stats->total_time_ns[BLOCK_ACCT_READ];
+        s->stats->flush_total_time_ns = stats->total_time_ns[BLOCK_ACCT_FLUSH];
+    }
 
     s->stats->wr_highest_offset = bs->wr_highest_offset;
 

include/block/block.h

@@ -621,6 +621,4 @@ void bdrv_io_plug(BlockDriverState *bs);
 void bdrv_io_unplug(BlockDriverState *bs);
 void bdrv_flush_io_queue(BlockDriverState *bs);
 
-BlockAcctStats *bdrv_get_stats(BlockDriverState *bs);
-
 #endif

include/block/block_int.h

@@ -399,9 +399,6 @@ struct BlockDriverState {
     unsigned       pending_reqs[2];
     QLIST_ENTRY(BlockDriverState) round_robin;
 
-    /* I/O stats (display with "info blockstats"). */
-    BlockAcctStats stats;
-
     /* Offset after the highest byte written to */
     uint64_t wr_highest_offset;