printk: Optimize if statement logic where newline exists

In reviewing Kay's fix up patch: "printk: Have printk() never buffer its
data", I found two if statements that could be combined and optimized.

Put together the two 'cont.len && cont.owner == current' if statements
into a single one, and check if we need to call cont_add(). This also
removes the unneeded double cont_flush() calls.

Link: http://lkml.kernel.org/r/1340869133.876.10.camel@mop
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/printk.c b/kernel/printk.c
index fbf4d0b..5ae6b09 100644 (file)
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1496,15 +1496,14 @@ asmlinkage int vprintk_emit(int facility, int level,
                bool stored = false;
 
                /*
-                * Flush the conflicting buffer. An earlier newline was missing,
-                * or we race with a continuation line from an interrupt.
+                * If an earlier newline was missing and it was the same task,
+                * either merge it with the current buffer and flush, or if
+                * there was a race with interrupts (prefix == true) then just
+                * flush it out and store this line separately.
                 */
-               if (cont.len && prefix && cont.owner == current)
-                       cont_flush();
-
-               /* Merge with our buffer if possible; flush it in any case */
                if (cont.len && cont.owner == current) {
-                       stored = cont_add(facility, level, text, text_len);
+                       if (!prefix)
+                               stored = cont_add(facility, level, text, text_len);
                        cont_flush();
                }