Jens Axboe <axboe@xxxxxxxxx> writes:
> On 2011-08-28 21:47, Namhyung Kim wrote:
>> Currently, bio_endio() lacks its completion tracepoint in it,
>> so that the bio-based devices - except DM which inserted the
>> tracepoint explicitly - cannot send us such an event when using
>> blktrace. Adding the tracepoint in the function will fix this.
>>
>> However, bio_endio() is also used for other ways like some
>> nested bio-handling path and request-based devices. Simply
>> adding will result in duplicated event for those cases. Thus
>> add new __bio_endio() function to do things as before but no
>> tracepoint. Similarly, __bio_io_error() helper was added too.
>
> Not crazy about this solution, it seems a little fragile. And it's hard
> to know what the difference between bio_endio() and __bio_endio() is
> without looking at the code.
>
> I think it would be cleaner to mark a bio as going inflight, so that we
> can check this flag on completion. If it's never been in flight, don't
> trigger a completion event trace for it.
OK. Sounds reasonable.
So, how about this:
diff --git a/block/blk-core.c b/block/blk-core.c
index 90e1ffdeb415..b70c086dc7c0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -164,6 +164,9 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
if (unlikely(rq->cmd_flags & REQ_QUIET))
set_bit(BIO_QUIET, &bio->bi_flags);
+ /* completion event was already reported in blk_update_request */
+ clear_bit(BIO_IN_FLIGHT, &bio->bi_flags);
+
bio->bi_size -= nbytes;
bio->bi_sector += (nbytes >> 9);
@@ -1545,6 +1548,8 @@ static inline void __generic_make_request(struct bio *bio)
trace_block_bio_queue(q, bio);
+ set_bit(BIO_IN_FLIGHT, &bio->bi_flags);
+
ret = q->make_request_fn(q, bio);
} while (ret);
diff --git a/fs/bio.c b/fs/bio.c
index 9bfade8a609b..0176ca4935c1 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1447,6 +1447,15 @@ void bio_endio(struct bio *bio, int error)
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
error = -EIO;
+ if (test_bit(BIO_IN_FLIGHT, &bio->bi_flags)) {
+ struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+
+ trace_block_bio_complete(q, bio, error);
+
+ /* prevent duplicated completion event report */
+ clear_bit(BIO_IN_FLIGHT, &bio->bi_flags);
+ }
+
if (bio->bi_end_io)
bio->bi_end_io(bio, error);
}
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 32f0076e844b..daa81a7d1522 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -98,6 +98,7 @@ struct bio {
#define BIO_FS_INTEGRITY 10 /* fs owns integrity data, not block layer */
#define BIO_QUIET 11 /* Make BIO Quiet */
#define BIO_MAPPED_INTEGRITY 12/* integrity metadata has been remapped */
+#define BIO_IN_FLIGHT 13 /* report I/O completion event */
#define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag)))
/*
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
