[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: NGuillaume Chazarain <guichaz@yahoo.fr>
Acked-By: NTim Bird <tim.bird@am.sony.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

kernel/printk.c

@@ -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] != '>') {
@@ -592,8 +592,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 					emit_log_char(default_message_loglevel
 						+ '0');
 					emit_log_char('>');
+					printed_len += 3;
 				}
-				printed_len += 3;
 			}
 			log_level_unknown = 0;
 			if (!*p)