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authorJun'ichi Nomura <j-nomura@ce.jp.nec.com>2009-10-01 21:16:13 +0200
committerJens Axboe <jens.axboe@oracle.com>2009-10-01 21:19:34 +0200
commitb0da3f0dada78832c9da03ad2152ae76bd9a2496 (patch)
tree58380f5d8f3c313fbb9fd0310509a408b38a0399 /kernel/trace/blktrace.c
parent67efc9258010da35b27b3854d0880c7e193004ed (diff)
downloadlinux-b0da3f0dada78832c9da03ad2152ae76bd9a2496.tar.bz2
Add a tracepoint for block request remapping
Since 2.6.31 now has request-based device-mapper, it's useful to have a tracepoint for request-remapping as well as bio-remapping. This patch adds a tracepoint for request-remapping, trace_block_rq_remap(). Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'kernel/trace/blktrace.c')
-rw-r--r--kernel/trace/blktrace.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 60b5c5a3d4b4..d9d6206e0b14 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -856,6 +856,37 @@ static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
}
/**
+ * blk_add_trace_rq_remap - Add a trace for a request-remap operation
+ * @q: queue the io is for
+ * @rq: the source request
+ * @dev: target device
+ * @from: source sector
+ *
+ * Description:
+ * Device mapper remaps request to other devices.
+ * Add a trace for that action.
+ *
+ **/
+static void blk_add_trace_rq_remap(struct request_queue *q,
+ struct request *rq, dev_t dev,
+ sector_t from)
+{
+ struct blk_trace *bt = q->blk_trace;
+ struct blk_io_trace_remap r;
+
+ if (likely(!bt))
+ return;
+
+ r.device_from = cpu_to_be32(dev);
+ r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
+ r.sector_from = cpu_to_be64(from);
+
+ __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
+ rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
+ sizeof(r), &r);
+}
+
+/**
* blk_add_driver_data - Add binary message with driver-specific data
* @q: queue the io is for
* @rq: io request
@@ -922,10 +953,13 @@ static void blk_register_tracepoints(void)
WARN_ON(ret);
ret = register_trace_block_remap(blk_add_trace_remap);
WARN_ON(ret);
+ ret = register_trace_block_rq_remap(blk_add_trace_rq_remap);
+ WARN_ON(ret);
}
static void blk_unregister_tracepoints(void)
{
+ unregister_trace_block_rq_remap(blk_add_trace_rq_remap);
unregister_trace_block_remap(blk_add_trace_remap);
unregister_trace_block_split(blk_add_trace_split);
unregister_trace_block_unplug_io(blk_add_trace_unplug_io);