[PATCH] vprintk support

Add vprintk call.  This lets us directly pass varargs stuff to the console
without using vsnprintf to an intermediate buffer.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/kernel.h

@@ -97,6 +97,7 @@ extern int __kernel_text_address(unsigned long addr);
 extern int kernel_text_address(unsigned long addr);
 extern int session_of_pgrp(int pgrp);
 
+asmlinkage int vprintk(const char *fmt, va_list args);
 asmlinkage int printk(const char * fmt, ...)
 	__attribute__ ((format (printf, 1, 2)));
 

kernel/printk.c

@@ -508,6 +508,17 @@ static void zap_locks(void)
 asmlinkage int printk(const char *fmt, ...)
 {
 	va_list args;
+	int r;
+
+	va_start(args, fmt);
+	r = vprintk(fmt, args);
+	va_end(args);
+
+	return r;
+}
+
+asmlinkage int vprintk(const char *fmt, va_list args)
+{
 	unsigned long flags;
 	int printed_len;
 	char *p;
@@ -521,9 +532,7 @@ asmlinkage int printk(const char *fmt, ...)
 	spin_lock_irqsave(&logbuf_lock, flags);
 
 	/* Emit the output into the temporary buffer */
-	va_start(args, fmt);
 	printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args);
-	va_end(args);
 
 	/*
 	 * Copy the output into log_buf.  If the caller didn't provide
@@ -575,6 +584,7 @@ asmlinkage int printk(const char *fmt, ...)
 	return printed_len;
 }
 EXPORT_SYMBOL(printk);
+EXPORT_SYMBOL(vprintk);
 
 /**
  * acquire_console_sem - lock the console system for exclusive use.