Commit 8835ca59 authored Oct 19, 2016 by Linus Torvalds

printk: suppress empty continuation lines



We have a fairly common pattern where you print several things as
continuations on one single line in a loop, and then at the end you do

	printk(KERN_CONT "\n");

to flush the buffered output.

But if the output was flushed by something else (concurrent printk
activity, or just system logging), we don't want that final flushing to
just print an empty line.

So just suppress empty continuation lines when they couldn't be merged
into the line they are a continuation of.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 63ae602c

kernel/printk/printk.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1769,6 +1769,10 @@ static size_t log_output(int facility, int level, enum log_flags lflags, const c
		cont_flush();
		}

		/* Skip empty continuation lines that couldn't be added - they just flush */
		if (!text_len && (lflags & LOG_CONT))
		return 0;

		/* If it doesn't end in a newline, try to buffer the current line */
		if (!(lflags & LOG_NEWLINE)) {
		if (cont_add(facility, level, lflags, text, text_len))

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