[PATCH AUTOSEL 4.14 109/127] blktrace: Show requests without sector

Sasha Levin
2019-11-22T05:59:38Z

From: Jan Kara <jack@suse.cz>

[ Upstream commit 0803de78049fe1b0baf44bcddc727b036fb9139b ]

Currently, blktrace will not show requests that don't have any data as
rq->__sector is initialized to -1 which is out of device range and thus
discarded by act_log_check(). This is most notably the case for cache
flush requests sent to the device. Fix the problem by making
blk_rq_trace_sector() return 0 for requests without initialized sector.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/blktrace_api.h | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index 8804753805ac5..7bb2d8de9f308 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -116,7 +116,13 @@ extern void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes);

static inline sector_t blk_rq_trace_sector(struct request *rq)
{
- return blk_rq_is_passthrough(rq) ? 0 : blk_rq_pos(rq);
+ /*
+ * Tracing should ignore starting sector for passthrough requests and
+ * requests where starting sector didn't get set.
+ */
+ if (blk_rq_is_passthrough(rq) || blk_rq_pos(rq) == (sector_t)-1)
+ return 0;
+ return blk_rq_pos(rq);
}

static inline unsigned int blk_rq_trace_nr_sectors(struct request *rq)
--
2.20.1