Added in MESSAGE notes for blktraces

Allows messages to be inserted into blktrace streams.

Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/block/blktrace.c b/block/blktrace.c
index b2cbb4e5d76..20e11f354f1 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -75,6 +75,20 @@ 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;
+        static char bt_msg_buf[BLK_TN_MAX_MSG];
+
+        va_start(args, fmt);
+        n = vscnprintf(bt_msg_buf, BLK_TN_MAX_MSG, fmt, args);
+        va_end(args);
+
+        trace_note(bt, 0, BLK_TN_MESSAGE, bt_msg_buf, n);
+}
+EXPORT_SYMBOL_GPL(__trace_note_message);
+
 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
                          pid_t pid)
 {