[PATCH 2/3] log: Add pr_cont helper

[Cyrill Gorcunov]

Sometimes we split output printing in several pr_ calls, which
causes log engine to inject time delta at the front of the record.
For example

 | (00.007461) Obtaining task stat ... (00.007497)

instead of ending delta there should be plain \n.

For this sake we introduce pr_cont() helper. It works similar
to what pr_cont in kernel does -- continues printing a line.

Note it's not multithread safe so don't use it outside of
dumping procedure. At least for now.

Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
---
 include/log.h |  4 ++++
 log.c         | 15 +++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/include/log.h b/include/log.h
index a38f441..30a6f24 100644
--- a/include/log.h
+++ b/include/log.h
@@ -57,4 +57,8 @@ extern void print_on_level(unsigned int loglevel, const char *format, ...)
 #define pr_perror(fmt, ...)							\
 	pr_err(fmt ": %m\n", ##__VA_ARGS__)
 
+#define pr_cont(fmt, ...)							\
+	print_on_level(LOG_CONT,						\
+		       LOG_PREFIX fmt, ##__VA_ARGS__)
+
 #endif /* __CR_LOG_H__ */
diff --git a/log.c b/log.c
index feb2263..fbbcf52 100644
--- a/log.c
+++ b/log.c
@@ -20,6 +20,7 @@
 #define DEFAULT_LOGFD		STDERR_FILENO
 
 static unsigned int current_loglevel = DEFAULT_LOGLEVEL;
+static unsigned int prev_print_at = DEFAULT_LOGLEVEL;
 
 static char buffer[PAGE_SIZE];
 static char buf_off = 0;
@@ -161,15 +162,25 @@ static void __print_on_level(unsigned int loglevel, const char *format, va_list
 {
 	int fd, size, ret, off;
 
-	if (unlikely(loglevel == LOG_MSG)) {
+	switch (loglevel) {
+	case LOG_MSG:
 		fd = STDOUT_FILENO;
 		off = buf_off;
-	} else {
+		break;
+	case LOG_CONT:
+		if (prev_print_at > current_loglevel)
+			return;
+		fd = log_get_fd();
+		off = buf_off;
+		break;
+	default:
+		prev_print_at = loglevel;
 		if (loglevel > current_loglevel)
 			return;
 		fd = log_get_fd();
 		print_ts();
 		off = 0;
+		break;
 	}
 
 	size  = vsnprintf(buffer + buf_off, PAGE_SIZE - buf_off, format, params);
-- 
1.8.1.4


--8t9RHnE3ZwKMSgU+--