Revert "block: add missing block_bio_complete() tracepoint"

This reverts commit acb7ff9c8f8d214d8e4f3c5cd4883a748ea99bd8.

Wanlong Gao reports that it causes a kernel panic on his machine several
minutes after boot. Reverting it removes the panic.

Jens says:
 "It's not quite clear why that is yet, so I think we should just revert
  the commit for 3.9 final (which I'm assuming is pretty close).

  The wifi is crap at the LSF hotel, so sending this email instead of
  queueing up a revert and pull request."

Reported-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Requested-by: Jens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <tj@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/block/blk-core.c b/block/blk-core.c
index 074b758efc42cf116d61f4755f0107f491890980..7c288358a745ad2312e93080201e341cf2b69207 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -39,6 +39,7 @@
 
 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 7e469260fe5eba5272ab56f74d9bd1c38fc2cfbf..9a0bdad9ad8fad49eaf8ee0d0ad916df247f0f3c 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -611,6 +611,7 @@ 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 24909eb13fec1b0bf22e40caa4ff7a76967f80e4..f4e87bfc7567923944d2fce13da4c7d636479566 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -184,6 +184,8 @@ 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;
        }
@@ -3914,6 +3916,8 @@ 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);
@@ -4382,6 +4386,8 @@ 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);
        }
 }
@@ -4758,8 +4764,11 @@ static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
                handled++;
        }
        remaining = raid5_dec_bi_active_stripes(raid_bio);
-       if (remaining == 0)
+       if (remaining == 0) {
+               trace_block_bio_complete(bdev_get_queue(raid_bio->bi_bdev),
+                                        raid_bio, 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 bb5768f59b32e22fdcde250f0ae8b01eb6b69b48..b96fc6ce485595f0179bc909c807ae197258e671 100644 (file)
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1428,8 +1428,6 @@ 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 0ea61e07a91c03053833faf3a4250e1f6023a10d..7c2e030e72f10542612ba34ce79b18f6b1b8ad06 100644 (file)
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -12,7 +12,6 @@
 
 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 9961726523d01251957b2f8c661422c31d1ac78c..9c1467357b03c616967cd193efab6506e3e5adff 100644 (file)
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -257,6 +257,7 @@ 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
  *
@@ -265,9 +266,9 @@ TRACE_EVENT(block_bio_bounce,
  */
 TRACE_EVENT(block_bio_complete,
 
-       TP_PROTO(struct bio *bio, int error),
+       TP_PROTO(struct request_queue *q, struct bio *bio, int error),
 
-       TP_ARGS(bio, error),
+       TP_ARGS(q, bio, error),
 
        TP_STRUCT__entry(
                __field( dev_t,         dev             )
@@ -278,8 +279,7 @@ TRACE_EVENT(block_bio_complete,
        ),
 
        TP_fast_assign(
-               __entry->dev            = bio->bi_bdev ?
-                                         bio->bi_bdev->bd_dev : 0;
+               __entry->dev            = bio->bi_bdev->bd_dev;
                __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 9e5b8c272eecc9121e8d3e064f30220c71c7e957..5a0f781cd729870892d105f24cc552a9d28b23e6 100644 (file)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -739,12 +739,6 @@ 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);
 }
 
@@ -780,24 +774,10 @@ 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 bio *bio, int error)
+static void blk_add_trace_bio_complete(void *ignore,
+                                      struct request_queue *q, 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);
 }