Commit 025510cd authored Jan 08, 2006 by Guillaume Chazarain Committed by Linus Torvalds Jan 08, 2006

[PATCH] printk return value: fix it



What's the true meaning of the printk return value?  Should it include the
priority prefix length of 3?  and what about the timing information?  In
both cases it was broken:

strace -e write echo 1 > /dev/kmsg
=> write(1, "1\n", 2)                      = 5
strace -e write echo "<1>1" > /dev/kmsg
=> write(1, "<1>1\n", 5)                   = 8

The returned length was "length of input string + 3", I made it "length
of string output to the log buffer".

Note that I couldn't find any printk caller in the kernel interested by its
return value besides kmsg_write.

Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr>
Acked-By: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 2520f14c

kernel/printk.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -569,7 +569,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
		p[1] <= '7' && p[2] == '>') {
		loglev_char = p[1];
		p += 3;
		printed_len += 3;
		printed_len -= 3;
		} else {
		loglev_char = default_message_loglevel
		+ '0';
		@@ -584,7 +584,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)

		for (tp = tbuf; tp < tbuf + tlen; tp++)
		emit_log_char(*tp);
		printed_len += tlen - 3;
		printed_len += tlen;
		} else {
		if (p[0] != '<' \|\| p[1] < '0' \|\|
		p[1] > '7' \|\| p[2] != '>') {
		@@ -592,9 +592,9 @@ asmlinkage int vprintk(const char *fmt, va_list args)
		emit_log_char(default_message_loglevel
		+ '0');
		emit_log_char('>');
		}
		printed_len += 3;
		}
		}
		log_level_unknown = 0;
		if (!*p)
		break;

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