Messages in this thread |  | | Date | Mon, 30 Jan 2012 15:38:57 +0900 | From | Namhyung Kim <> | Subject | Re: [PATCH] block: add missing block_bio_complete() tracepoint |
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2012-01-29 6:41 PM, Namhyung Kim wrote: > The block_bio_complete() TP has been missed so long, so that bio-based > drivers haven't been able to trace its IO behavior. Add it. > > In some rare cases, such as loop_switch, @bio->bi_bdev can be NULL. > Thus convert it to TRACE_EVENT_CONDITION() as Steven suggested. >
Now I see that it seems TRACE_EVENT_CONDITION() can protect event tracing from such condition, but what about other users of the TP like blktrace? I think it'll still get NULL pointer dereference on bdev_get_queue() after the change, right? If so, convert to T_E_C() looks meaningless IMHO. Do I miss something?
Thanks, Namhyung
> From now on, request-based drivers will also get BLK_TA_COMPLETEs for > all bio's in requests. This needs to be handled in userland properly. > > Also remove external use of the TP in DM and unexport it. > > Signed-off-by: Namhyung Kim <namhyung@gmail.com> > Cc: Tejun Heo <tj@kernel.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: dm-devel@redhat.com > --- > * v2: > - Merge previous patches into one as suggested by Tejun. > - Drop BIO_COMPLETE_MASK. Now I think it should be handled in userland > like other (maybe duplicated, in some sense) bio complete reports. > > block/blk-core.c | 1 - > drivers/md/dm.c | 1 - > fs/bio.c | 2 ++ > include/trace/events/block.h | 4 +++- > 4 files changed, 5 insertions(+), 3 deletions(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index 1b4fd93af2c0..399c128f516c 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -37,7 +37,6 @@ > > EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); > EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); > -EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); > > DEFINE_IDA(blk_queue_ida); > > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index 4720f68f817e..01185fa0eb74 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -648,7 +648,6 @@ static void dec_pending(struct dm_io *io, int error) > queue_io(md, bio); > } else { > /* done with normal IO or empty flush */ > - trace_block_bio_complete(md->queue, bio, io_error); > bio_endio(bio, io_error); > } > } > diff --git a/fs/bio.c b/fs/bio.c > index b1fe82cf88cf..14c03eaf384e 100644 > --- a/fs/bio.c > +++ b/fs/bio.c > @@ -1447,6 +1447,8 @@ void bio_endio(struct bio *bio, int error) > else if (!test_bit(BIO_UPTODATE,&bio->bi_flags)) > error = -EIO; > > + trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio, error); > + > if (bio->bi_end_io) > bio->bi_end_io(bio, error); > } > diff --git a/include/trace/events/block.h b/include/trace/events/block.h > index 05c5e61f0a7c..96955f4828b3 100644 > --- a/include/trace/events/block.h > +++ b/include/trace/events/block.h > @@ -213,12 +213,14 @@ TRACE_EVENT(block_bio_bounce, > * This tracepoint indicates there is no further work to do on this > * block IO operation @bio. > */ > -TRACE_EVENT(block_bio_complete, > +TRACE_EVENT_CONDITION(block_bio_complete, > > TP_PROTO(struct request_queue *q, struct bio *bio, int error), > > TP_ARGS(q, bio, error), > > + TP_CONDITION(bio->bi_bdev != NULL), > + > TP_STRUCT__entry( > __field( dev_t, dev ) > __field( sector_t, sector )
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