blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.

In blk_add_trace_rq, we only chose the minor 2 bits from
request's cmd_flags and did some check for discard.
so most of other flags(e.g, REQ_SYNC) are missing.

For example, with a sync write after blkparse we get:
  8,16   1        1     0.001776503  7509  A  WS 1349632 + 1024 <- (8,17) 1347584
  8,16   1        2     0.001776813  7509  Q  WS 1349632 + 1024 [dd]
  8,16   1        3     0.001780395  7509  G  WS 1349632 + 1024 [dd]
  8,16   1        5     0.001783186  7509  I   W 1349632 + 1024 [dd]
  8,16   1       11     0.001816987  7509  D   W 1349632 + 1024 [dd]
  8,16   0        2     0.006218192     0  C   W 1349632 + 1024 [0]

Since now we have integrated the flags of both bio and request,
it is safe to pass rq->cmd_flags directly to __blk_add_trace.

With this patch, after a sync write we get:
  8,16   1        1     0.001776900  5425  A  WS 1189888 + 1024 <- (8,17) 1187840
  8,16   1        2     0.001777179  5425  Q  WS 1189888 + 1024 [dd]
  8,16   1        3     0.001780797  5425  G  WS 1189888 + 1024 [dd]
  8,16   1        5     0.001783402  5425  I  WS 1189888 + 1024 [dd]
  8,16   1       11     0.001817468  5425  D  WS 1189888 + 1024 [dd]
  8,16   0        2     0.005640709     0  C  WS 1189888 + 1024 [0]

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 4 insertions, 11 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index cbafed7d4f38..7aa40f8e182d 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -703,28 +703,21 @@ void blk_trace_shutdown(struct request_queue *q)
  *
  **/
 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
-                                    u32 what)
+                             u32 what)
 {
         struct blk_trace *bt = q->blk_trace;
-        int rw = rq->cmd_flags & 0x03;
 
         if (likely(!bt))
                 return;
 
-        if (rq->cmd_flags & REQ_DISCARD)
-                rw |= REQ_DISCARD;
-
-        if (rq->cmd_flags & REQ_SECURE)
-                rw |= REQ_SECURE;
-
         if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
                 what |= BLK_TC_ACT(BLK_TC_PC);
-                __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
+                __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
                                 what, rq->errors, rq->cmd_len, rq->cmd);
         } else  {
                 what |= BLK_TC_ACT(BLK_TC_FS);
-                __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
-                                what, rq->errors, 0, NULL);
+                __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
+                                rq->cmd_flags, what, rq->errors, 0, NULL);
         }
 }