Merge tag 'trace-seq-buf-3.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixlet from Steven Rostedt:
 "Remove unnecessary preempt_disable in printk()"

* tag 'trace-seq-buf-3.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  printk: Do not disable preemption for accessing printk_func

1 files changed, 8 insertions, 2 deletions

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index f900dc9f68224..02d6b6d287969 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1857,10 +1857,16 @@ asmlinkage __visible int printk(const char *fmt, ...)
 	int r;
 
 	va_start(args, fmt);
-	preempt_disable();
+
+	/*
+	 * If a caller overrides the per_cpu printk_func, then it needs
+	 * to disable preemption when calling printk(). Otherwise
+	 * the printk_func should be set to the default. No need to
+	 * disable preemption here.
+	 */
 	vprintk_func = this_cpu_read(printk_func);
 	r = vprintk_func(fmt, args);
-	preempt_enable();
+
 	va_end(args);
 
 	return r;