block: trace all devices plug operation
authorJianpeng Ma <majianpeng@gmail.com>
Wed, 11 Sep 2013 19:21:07 +0000 (13:21 -0600)
committerJens Axboe <axboe@kernel.dk>
Wed, 11 Sep 2013 19:21:07 +0000 (13:21 -0600)
commit7aef2e780b13973ea60aed8c556107dabde6a495
tree5265a24ffeaea32e2cefacf83962764d6d661a36
parent6e4664525b1db28f8c4e1130957f70a94c19213e
block: trace all devices plug operation

In func blk_queue_bio, if list of plug is empty,it will call
blk_trace_plug.
If process deal with a single device,it't ok.But if process deal with
multi devices,it only trace the first device.
Using request_count to judge, it can soleve this problem.

In addition, i modify the comment.

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/blk-core.c