On 6/23/20 11:48 PM, Christoph Hellwig wrote:

On Tue, Jun 23, 2020 at 08:27:52PM -0700, Chaitanya Kulkarni wrote:

quoted

There are many places where trace API accepts the struct request_queue*
parameter which can be derived from other function parameters.

This patch removes the struct request queue parameter from the
blktrace framework and adjusts the tracepoints definition and usage
along with the tracing API itself.

Good idea, and I had a half-ready patch for this already as well.

Well, I sent out the reply to your suggestion didn't get any response so 
I decided to send a patch, if you want we can merge it I'll keep you as 
an author for the right reasons.

One issue, and two extra requests below:

quoted

  	if (bio->bi_disk && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
-		trace_block_bio_complete(bio->bi_disk->queue, bio);
+		trace_block_bio_complete(bio);

This one can also be called for a different queue than
bio->bi_disk->queue, so for this one particular tracepoint we'll need
to keep the request_queue argument.

Yes, we should.

quoted

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index fdcc2c1dd178..a3cade16ef80 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c

@@ -409,7 +409,7 @@ EXPORT_SYMBOL_GPL(blk_mq_sched_try_insert_merge);
  
  void blk_mq_sched_request_inserted(struct request *rq)
  {
-	trace_block_rq_insert(rq->q, rq);
+	trace_block_rq_insert(rq);
  }
  EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted);

As a follow on patch we should also remove this function.

Okay will make it is a 2nd patch.

quoted

  	}
  
  	spin_lock(&ctx->lock);

@@ -2111,7 +2111,7 @@ blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
  		goto queue_exit;
  	}
  
-	trace_block_getrq(q, bio, bio->bi_opf);
+	trace_block_getrq(bio, bio->bi_opf);

The second argument can be removed as well.  Maybe as another patch.

Okay I'll make it in a 3rd patch.