aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorTejun Heo <tj@kernel.org>2013-01-11 13:06:33 -0800
committerJens Axboe <axboe@kernel.dk>2013-01-14 15:00:36 +0100
commit3a366e614d0837d9fc23f78cdb1a1186ebc3387f (patch)
tree5be6ec716687234ac1e6202db62c84ee1d2246be
parentac9a19745196388ae5d828c0be7a1d6e472101f3 (diff)
downloadvexpress-lsk-3a366e614d0837d9fc23f78cdb1a1186ebc3387f.tar.gz
block: add missing block_bio_complete() tracepoint
bio completion didn't kick block_bio_complete TP. Only dm was explicitly triggering the TP on IO completion. This makes block_bio_complete TP useless for tracers which want to know about bios, and all other bio based drivers skip generating blktrace completion events. This patch makes all bio completions via bio_endio() generate block_bio_complete TP. * Explicit trace_block_bio_complete() invocation removed from dm and the trace point is unexported. * @rq dropped from trace_block_bio_complete(). bios may fly around w/o queue associated. Verifying and accessing the assocaited queue belongs to TP probes. * blktrace now gets both request and bio completions. Make it ignore bio completions if request completion path is happening. This makes all bio based drivers generate blktrace completion events properly and makes the block_bio_complete TP actually useful. v2: With this change, block_bio_complete TP could be invoked on sg commands which have bio's with %NULL bi_bdev. Update TP assignment code to check whether bio->bi_bdev is %NULL before dereferencing. Signed-off-by: Tejun Heo <tj@kernel.org> Original-patch-by: Namhyung Kim <namhyung@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alasdair Kergon <agk@redhat.com> Cc: dm-devel@redhat.com Cc: Neil Brown <neilb@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--block/blk-core.c1
-rw-r--r--drivers/md/dm.c1
-rw-r--r--drivers/md/raid5.c11
-rw-r--r--fs/bio.c2
-rw-r--r--include/linux/blktrace_api.h1
-rw-r--r--include/trace/events/block.h8
-rw-r--r--kernel/trace/blktrace.c26
7 files changed, 31 insertions, 19 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index aca5d82ff13..4f5aec708be 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -39,7 +39,6 @@
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
-EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
DEFINE_IDA(blk_queue_ida);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c72e4d5a961..650ec2866e3 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -627,7 +627,6 @@ 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/drivers/md/raid5.c b/drivers/md/raid5.c
index 19d77a02663..9ab506df42d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -184,8 +184,6 @@ static void return_io(struct bio *return_bi)
return_bi = bi->bi_next;
bi->bi_next = NULL;
bi->bi_size = 0;
- trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
- bi, 0);
bio_endio(bi, 0);
bi = return_bi;
}
@@ -3917,8 +3915,6 @@ static void raid5_align_endio(struct bio *bi, int error)
rdev_dec_pending(rdev, conf->mddev);
if (!error && uptodate) {
- trace_block_bio_complete(bdev_get_queue(raid_bi->bi_bdev),
- raid_bi, 0);
bio_endio(raid_bi, 0);
if (atomic_dec_and_test(&conf->active_aligned_reads))
wake_up(&conf->wait_for_stripe);
@@ -4377,8 +4373,6 @@ static void make_request(struct mddev *mddev, struct bio * bi)
if ( rw == WRITE )
md_write_end(mddev);
- trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
- bi, 0);
bio_endio(bi, 0);
}
}
@@ -4755,11 +4749,8 @@ static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
handled++;
}
remaining = raid5_dec_bi_active_stripes(raid_bio);
- if (remaining == 0) {
- trace_block_bio_complete(bdev_get_queue(raid_bio->bi_bdev),
- raid_bio, 0);
+ if (remaining == 0)
bio_endio(raid_bio, 0);
- }
if (atomic_dec_and_test(&conf->active_aligned_reads))
wake_up(&conf->wait_for_stripe);
return handled;
diff --git a/fs/bio.c b/fs/bio.c
index b96fc6ce485..bb5768f59b3 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1428,6 +1428,8 @@ void bio_endio(struct bio *bio, int error)
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
error = -EIO;
+ trace_block_bio_complete(bio, error);
+
if (bio->bi_end_io)
bio->bi_end_io(bio, error);
}
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index 7c2e030e72f..0ea61e07a91 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -12,6 +12,7 @@
struct blk_trace {
int trace_state;
+ bool rq_based;
struct rchan *rchan;
unsigned long __percpu *sequence;
unsigned char __percpu *msg_data;
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 05c5e61f0a7..8a168db9a64 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -206,7 +206,6 @@ TRACE_EVENT(block_bio_bounce,
/**
* block_bio_complete - completed all work on the block operation
- * @q: queue holding the block operation
* @bio: block operation completed
* @error: io error value
*
@@ -215,9 +214,9 @@ TRACE_EVENT(block_bio_bounce,
*/
TRACE_EVENT(block_bio_complete,
- TP_PROTO(struct request_queue *q, struct bio *bio, int error),
+ TP_PROTO(struct bio *bio, int error),
- TP_ARGS(q, bio, error),
+ TP_ARGS(bio, error),
TP_STRUCT__entry(
__field( dev_t, dev )
@@ -228,7 +227,8 @@ TRACE_EVENT(block_bio_complete,
),
TP_fast_assign(
- __entry->dev = bio->bi_bdev->bd_dev;
+ __entry->dev = bio->bi_bdev ?
+ bio->bi_bdev->bd_dev : 0;
__entry->sector = bio->bi_sector;
__entry->nr_sector = bio->bi_size >> 9;
__entry->error = error;
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index c0bd0308741..190d98fbed2 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -739,6 +739,12 @@ static void blk_add_trace_rq_complete(void *ignore,
struct request_queue *q,
struct request *rq)
{
+ struct blk_trace *bt = q->blk_trace;
+
+ /* if control ever passes through here, it's a request based driver */
+ if (unlikely(bt && !bt->rq_based))
+ bt->rq_based = true;
+
blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
}
@@ -774,10 +780,24 @@ static void blk_add_trace_bio_bounce(void *ignore,
blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
}
-static void blk_add_trace_bio_complete(void *ignore,
- struct request_queue *q, struct bio *bio,
- int error)
+static void blk_add_trace_bio_complete(void *ignore, struct bio *bio, int error)
{
+ struct request_queue *q;
+ struct blk_trace *bt;
+
+ if (!bio->bi_bdev)
+ return;
+
+ q = bdev_get_queue(bio->bi_bdev);
+ bt = q->blk_trace;
+
+ /*
+ * Request based drivers will generate both rq and bio completions.
+ * Ignore bio ones.
+ */
+ if (likely(!bt) || bt->rq_based)
+ return;
+
blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
}