block: explicit I/O accounting

Decouple the I/O accounting from bdrv_aio_readv/writev/flush and
make the hardware models call directly into the accounting helpers.

This means:
 - we do not count internal requests from image formats in addition
   to guest originating I/O
 - we do not double count I/O ops if the device model handles it
   chunk wise
 - we only account I/O once it actuall is done
 - can extent I/O accounting to synchronous or coroutine I/O easily
 - implement I/O latency tracking easily (see the next patch)

I've conveted the existing device model callers to the new model,
device models that are using synchronous I/O and weren't accounted
before haven't been updated yet.  Also scsi hasn't been converted
to the end-to-end accounting as I want to defer that after the pending
scsi layer overhaul.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/block_int.h b/block_int.h
index f1480d6..5f8050d 100644
--- a/block_int.h
+++ b/block_int.h
@@ -184,11 +184,8 @@ struct BlockDriverState {
     void *sync_aiocb;
 
     /* I/O stats (display with "info blockstats"). */
-    uint64_t rd_bytes;
-    uint64_t wr_bytes;
-    uint64_t rd_ops;
-    uint64_t wr_ops;
-    uint64_t flush_ops;
+    uint64_t nr_bytes[BDRV_MAX_IOTYPE];
+    uint64_t nr_ops[BDRV_MAX_IOTYPE];
     uint64_t wr_highest_sector;
 
     /* Whether the disk can expand beyond total_sectors */