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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Johannes Thumshirn <jthumshirn@suse.de>,
        Jan Kara <jack@suse.cz>, Jens Axboe <axboe@kernel.dk>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 137/209] blktrace: Show requests without sector
Date:   Wed,  4 Dec 2019 18:55:49 +0100
Message-Id: <20191204175332.699738686@linuxfoundation.org>
In-Reply-To: <20191204175321.609072813@linuxfoundation.org>
References: <20191204175321.609072813@linuxfoundation.org>
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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