writeback: rename variables in trace_balance_dirty_pages()

Rename bdi_setpoint and bdi_dirty in the tracepoint to wb_setpoint and
wb_dirty, respectively. These changes were omitted by Tejun in the cgroup
writeback patchset.

Link: https://lkml.kernel.org/r/20250304110318.159567-3-yizhou.tang@shopee.com
Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Tang Yizhou

include/trace/events/writeback.h

@@ -646,8 +646,8 @@ TRACE_EVENT(balance_dirty_pages,
 		__field(unsigned long,	limit)
 		__field(unsigned long,	setpoint)
 		__field(unsigned long,	dirty)
-		__field(unsigned long,	bdi_setpoint)
-		__field(unsigned long,	bdi_dirty)
+		__field(unsigned long,	wb_setpoint)
+		__field(unsigned long,	wb_dirty)
 		__field(unsigned long,	dirty_ratelimit)
 		__field(unsigned long,	task_ratelimit)
 		__field(unsigned int,	dirtied)
@@ -667,9 +667,9 @@ TRACE_EVENT(balance_dirty_pages,
 		__entry->setpoint	= (global_wb_domain.dirty_limit +
 						freerun) / 2;
 		__entry->dirty		= dtc->dirty;
-		__entry->bdi_setpoint	= __entry->setpoint *
+		__entry->wb_setpoint	= __entry->setpoint *
 						dtc->wb_thresh / (dtc->thresh + 1);
-		__entry->bdi_dirty	= dtc->wb_dirty;
+		__entry->wb_dirty	= dtc->wb_dirty;
 		__entry->dirty_ratelimit = KBps(dirty_ratelimit);
 		__entry->task_ratelimit	= KBps(task_ratelimit);
 		__entry->dirtied	= dirtied;
@@ -685,16 +685,16 @@ TRACE_EVENT(balance_dirty_pages,
 
 	TP_printk("bdi %s: "
 		  "limit=%lu setpoint=%lu dirty=%lu "
-		  "bdi_setpoint=%lu bdi_dirty=%lu "
+		  "wb_setpoint=%lu wb_dirty=%lu "
 		  "dirty_ratelimit=%lu task_ratelimit=%lu "
 		  "dirtied=%u dirtied_pause=%u "
 		  "paused=%lu pause=%ld period=%lu think=%ld cgroup_ino=%lu",
 		  __entry->bdi,
 		  __entry->limit,
 		  __entry->setpoint,
 		  __entry->dirty,
-		  __entry->bdi_setpoint,
-		  __entry->bdi_dirty,
+		  __entry->wb_setpoint,
+		  __entry->wb_dirty,
 		  __entry->dirty_ratelimit,
 		  __entry->task_ratelimit,
 		  __entry->dirtied,