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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2014-12-11 09:12:01 -0500
committerSteven Rostedt <rostedt@goodmis.org>2014-12-11 09:12:01 -0500
commit1fb8915b9876a80f43732980208b39d013f8da9d (patch)
tree73a82f42c9601dd1155092ff7283476fe9d625e6 /kernel
parentdb0865543739b3edb2ee9bf340380cf4986b58ff (diff)
printk: Do not disable preemption for accessing printk_func
As printk_func will either be the default function, or a per_cpu function for the current CPU, there's no reason to disable preemption to access it from printk. That's because if the printk_func is not the default then the caller had better disabled preemption as they were the one to change it. Link: http://lkml.kernel.org/r/CA+55aFz5-_LKW4JHEBoWinN9_ouNcGRWAF2FUA35u46FRN-Kxw@mail.gmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/printk/printk.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 5af2b8bc88f0..9b896e7a50a9 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1859,10 +1859,16 @@ 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;