block: use standard blktrace API to output cgroup info for debug notes

Currently cfq/bfq/blk-throttle output cgroup info in trace in their own
way. Now we have standard blktrace API for this, so convert them to use
it.

Note, this changes the behavior a little bit. cgroup info isn't output
by default, we only do this with 'blk_cgroup' option enabled. cgroup
info isn't output as a string by default too, we only do this with
'blk_cgname' option enabled. Also cgroup info is output in different
position of the note string. I think these behavior changes aren't a big
issue (actually we make trace data shorter which is good), since the
blktrace note is solely for debugging.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 9 insertions, 4 deletions

diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index d2e908586e3d..67b4d4dfc19c 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -28,10 +28,12 @@ struct blk_trace {
         atomic_t dropped;
 };
 
+struct blkcg;
+
 extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);
 extern void blk_trace_shutdown(struct request_queue *);
-extern __printf(2, 3)
-void __trace_note_message(struct blk_trace *, const char *fmt, ...);
+extern __printf(3, 4)
+void __trace_note_message(struct blk_trace *, struct blkcg *blkcg, const char *fmt, ...);
 
 /**
  * blk_add_trace_msg - Add a (simple) message to the blktrace stream
@@ -46,12 +48,14 @@ void __trace_note_message(struct blk_trace *, const char *fmt, ...);
  *     NOTE: Can not use 'static inline' due to presence of var args...
  *
  **/
-#define blk_add_trace_msg(q, fmt, ...)                                  \
+#define blk_add_cgroup_trace_msg(q, cg, fmt, ...)                       \
         do {                                                            \
                 struct blk_trace *bt = (q)->blk_trace;                  \
                 if (unlikely(bt))                                       \
-                        __trace_note_message(bt, fmt, ##__VA_ARGS__);   \
+                        __trace_note_message(bt, cg, fmt, ##__VA_ARGS__);\
         } while (0)
+#define blk_add_trace_msg(q, fmt, ...)                                  \
+        blk_add_cgroup_trace_msg(q, NULL, fmt, ##__VA_ARGS__)
 #define BLK_TN_MAX_MSG          128
 
 static inline bool blk_trace_note_message_enabled(struct request_queue *q)
@@ -82,6 +86,7 @@ extern struct attribute_group blk_trace_attr_group;
 # define blk_trace_startstop(q, start)                  (-ENOTTY)
 # define blk_trace_remove(q)                            (-ENOTTY)
 # define blk_add_trace_msg(q, fmt, ...)                 do { } while (0)
+# define blk_add_cgroup_trace_msg(q, cg, fmt, ...)      do { } while (0)
 # define blk_trace_remove_sysfs(dev)                    do { } while (0)
 # define blk_trace_note_message_enabled(q)              (false)
 static inline int blk_trace_init_sysfs(struct device *dev)