1 files changed, 23 insertions, 0 deletions

diff --git a/block/blktrace.c b/block/blktrace.c
index b2cbb4e..7ae87cc 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -75,6 +75,23 @@ static void trace_note_time(struct blk_trace *bt)
 	local_irq_restore(flags);
 }
 
+void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
+{
+	int n;
+	va_list args;
+	char *buf;
+
+	preempt_disable();
+	buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
+	va_start(args, fmt);
+	n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
+	va_end(args);
+
+	trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(__trace_note_message);
+
 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
 			 pid_t pid)
 {
@@ -232,6 +249,7 @@ static void blk_trace_cleanup(struct blk_trace *bt)
 	debugfs_remove(bt->dropped_file);
 	blk_remove_tree(bt->dir);
 	free_percpu(bt->sequence);
+	free_percpu(bt->msg_data);
 	kfree(bt);
 }
 
@@ -346,6 +364,10 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	if (!bt->sequence)
 		goto err;
 
+	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
+	if (!bt->msg_data)
+		goto err;
+
 	ret = -ENOENT;
 	dir = blk_create_tree(buts->name);
 	if (!dir)
@@ -392,6 +414,7 @@ err:
 		if (bt->dropped_file)
 			debugfs_remove(bt->dropped_file);
 		free_percpu(bt->sequence);
+		free_percpu(bt->msg_data);
 		if (bt->rchan)
 			relay_close(bt->rchan);
 		kfree(bt);