blktrace: Show requests without sector

jankara · axboe · commit 0803de78049f · 2019-02-07T12:57:17.000-07:00
Currently, blktrace will not show requests that don't have any data as
rq-&gt;__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 &lt;jthumshirn@suse.de&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
diff --git 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)

Original file line number	Diff line number	Diff line change
`@@ -116,7 +116,13 @@ extern void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes);`
`116`	`116`
`117`	`117`	`static inline sector_t blk_rq_trace_sector(struct request *rq)`
`118`	`118`	`{`
`119`		`- return blk_rq_is_passthrough(rq) ? 0 : blk_rq_pos(rq);`
	`119`	`+ /*`
	`120`	`+ * Tracing should ignore starting sector for passthrough requests and`
	`121`	`+ * requests where starting sector didn't get set.`
	`122`	`+ */`
	`123`	`+ if (blk_rq_is_passthrough(rq) \|\| blk_rq_pos(rq) == (sector_t)-1)`
	`124`	`+ return 0;`
	`125`	`+ return blk_rq_pos(rq);`
`120`	`126`	`}`
`121`	`127`
`122`	`128`	`static inline unsigned int blk_rq_trace_nr_sectors(struct request *rq)`