If BIO is discarded or cross over end of device,
BIO queueing trial doesn't occur.
Actually the trace was called just before make_request at first:
[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23
2056a782f8e7e65fd4bfd027506b4ce1c5e9ccd4
And then 2 patches added some checks between them:
[PATCH] md: check bio address after mapping through partitions
5ddfe9691c91a244e8d1be597b6428fcefd58103,
[BLOCK] Don't allow empty barriers to be passed down to
queues that don't grok them
51fd77bd9f512ab6cc9df0733ba1caaab89eb957
It breaks original goal.
Let's trace it only when it happens.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
01edede41e