blktrace: port to tracepoints

This was a forward port of work done by Mathieu Desnoyers, I changed it to
encode the 'what' parameter on the tracepoint name, so that one can register
interest in specific events and not on classes of events to then check the
'what' parameter.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/md/dm.c

@@ -21,6 +21,7 @@
 #include <linux/idr.h>
 #include <linux/hdreg.h>
 #include <linux/blktrace_api.h>
+#include <trace/block.h>
 
 #define DM_MSG_PREFIX "core"
 
@@ -504,8 +505,7 @@ static void dec_pending(struct dm_io *io, int error)
 		end_io_acct(io);
 
 		if (io->error != DM_ENDIO_REQUEUE) {
-			blk_add_trace_bio(io->md->queue, io->bio,
-					  BLK_TA_COMPLETE);
+			trace_block_bio_complete(io->md->queue, io->bio);
 
 			bio_endio(io->bio, io->error);
 		}
@@ -598,7 +598,7 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
 	if (r == DM_MAPIO_REMAPPED) {
 		/* the bio has been remapped so dispatch it */
 
-		blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
+		trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
 				    tio->io->bio->bi_bdev->bd_dev,
 				    clone->bi_sector, sector);