On Tue, 10 Nov 2015 05:21:16 +0800
Chen Gang <xili_gchen_5...@hotmail.com> wrote:
> >From 0af9ca7a33b977d92498d990cb6f2a326dbad4f8 Mon Sep 17 00:00:00 2001
> From: Chen Gang <gang.chen.5...@gmail.com>
> Date: Tue, 10 Nov 2015 05:15:15 +0800
> Subject: [PATCH] kernel/trace/trace.c: Switch the related code with
> CONFIG_TRACER_MAX_TRACE
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
>
> tracing_max_lat_fops is used only when TRACER_MAX_TRACE enabled, so also
> swith the related code. The related warning with defconfig under x86_64:
>
> CC kernel/trace/trace.o
> kernel/trace/trace.c:5466:37: warning: ‘tracing_max_lat_fops’ defined but
> not used [-Wunused-const-variable]
> static const struct file_operations tracing_max_lat_fops = {
I'm curious to what compiler are you using? Because, for me gcc simply
compiles it out without any warning or anything because it's labeled as
a constant.
I'm not against the patch, but I simply don't get this warning. If I
remove the "const" then I do.
-- Steve
>
> Signed-off-by: Chen Gang <gang.chen.5...@gmail.com>
> ---
> kernel/trace/trace.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index b115826..87fb980 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -4548,6 +4548,8 @@ out:
> return ret;
> }
>
> +#ifdef CONFIG_TRACER_MAX_TRACE
> +
> static ssize_t
> tracing_max_lat_read(struct file *filp, char __user *ubuf,
> size_t cnt, loff_t *ppos)
> @@ -4562,6 +4564,8 @@ tracing_max_lat_write(struct file *filp, const char
> __user *ubuf,
> return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
> }
>
> +#endif
> +
> static int tracing_open_pipe(struct inode *inode, struct file *filp)
> {
> struct trace_array *tr = inode->i_private;
> @@ -5463,12 +5467,14 @@ static const struct file_operations
> tracing_thresh_fops = {
> .llseek = generic_file_llseek,
> };
>
> +#ifdef CONFIG_TRACER_MAX_TRACE
> static const struct file_operations tracing_max_lat_fops = {
> .open = tracing_open_generic,
> .read = tracing_max_lat_read,
> .write = tracing_max_lat_write,
> .llseek = generic_file_llseek,
> };
> +#endif
>
> static const struct file_operations set_tracer_fops = {
> .open = tracing_open_generic,
> --
> 1.9.3
>
>
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