From 5b85afa68e4f56c27f1d5c6f49e5257bce6448e6 Mon Sep 17 00:00:00 2001
From: Roman Pen <r.peniaev@gmail.com>
Date: Tue, 4 Mar 2014 23:13:10 +0900
Subject: [PATCH] blktrace: fix accounting of partially completed requests

commit af5040da01ef980670b3741b3e10733ee3e33566 upstream.

trace_block_rq_complete does not take into account that request can
be partially completed, so we can get the following incorrect output
of blkparser:

  C   R 232 + 240 [0]
  C   R 240 + 232 [0]
  C   R 248 + 224 [0]
  C   R 256 + 216 [0]

but should be:

  C   R 232 + 8 [0]
  C   R 240 + 8 [0]
  C   R 248 + 8 [0]
  C   R 256 + 8 [0]

Also, the whole output summary statistics of completed requests and
final throughput will be incorrect.

This patch takes into account real completion size of the request and
fixes wrong completion accounting.

Signed-off-by: Roman Pen <r.peniaev@gmail.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: linux-kernel@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
[bwh: Backported to 3.2: drop change in blk-mq.c]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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