Re: [PATCH 1/1] driver-core: Shut up dev_dbg_reatelimited() without DEBUG

[Antti Palosaari <crope@iki.fi>]

Hello Hiroshi,

On 08/21/2012 10:02 AM, Hiroshi Doyu wrote:
> Antti Palosaari <crope@iki.fi> wrote @ Mon, 20 Aug 2012 23:29:34 +0200:
>
>> On 08/20/2012 02:14 PM, Hiroshi Doyu wrote:
>>> Hi Antti,
>>>
>>> Antti Palosaari <crope@iki.fi> wrote @ Sat, 18 Aug 2012 02:11:56 +0200:
>>>
>>>> On 08/17/2012 09:04 AM, Hiroshi Doyu wrote:
>>>>> dev_dbg_reatelimited() without DEBUG printed "217078 callbacks
>>>>> suppressed". This shouldn't print anything without DEBUG.
>>>>>
>>>>> Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
>>>>> Reported-by: Antti Palosaari <crope@iki.fi>
>>>>> ---
>>>>>     include/linux/device.h |    6 +++++-
>>>>>     1 files changed, 5 insertions(+), 1 deletions(-)
>>>>>
>>>>> diff --git a/include/linux/device.h b/include/linux/device.h
>>>>> index eb945e1..d4dc26e 100644
>>>>> --- a/include/linux/device.h
>>>>> +++ b/include/linux/device.h
>>>>> @@ -962,9 +962,13 @@ do {									\
>>>>>     	dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
>>>>>     #define dev_info_ratelimited(dev, fmt, ...)				\
>>>>>     	dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
>>>>> +#if defined(DEBUG)
>>>>>     #define dev_dbg_ratelimited(dev, fmt, ...)				\
>>>>>     	dev_level_ratelimited(dev_dbg, dev, fmt, ##__VA_ARGS__)
>>>>> -
>>>>> +#else
>>>>> +#define dev_dbg_ratelimited(dev, fmt, ...)			\
>>>>> +	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
>>>>> +#endif
>>>>>     /*
>>>>>      * Stupid hackaround for existing uses of non-printk uses dev_info
>>>>>      *
>>>>>
>>>>
>>>> NACK. I don't think that's correct behavior. After that patch it kills
>>>> all output of dev_dbg_ratelimited(). If I use dynamic debugs and order
>>>> debugs, I expect to see debugs as earlier.
>>>
>>> You are right. I attached the update patch, just moving *_ratelimited
>>> functions after dev_dbg() definitions.
>>>
>>> With DEBUG defined/undefined in your "test.ko", it works fine. With
>>> CONFIG_DYNAMIC_DEBUG, it works with "+p", but with "-p", still
>>> "..callbacks suppressed" is printed.
>>
>> I am using dynamic debugs and behavior is now just same as it was when
>> reported that bug. OK, likely for static debug it is now correct.
>
> The following patch can also refrain "..callbacks suppressed" with
> "-p". I think that it's ok for all cases.
>
>>From b4c6aa9160f03b61ed17975c73db36c983a48927 Mon Sep 17 00:00:00 2001
> From: Hiroshi Doyu <hdoyu@nvidia.com>
> Date: Mon, 20 Aug 2012 13:49:19 +0300
> Subject: [v3 1/1] driver-core: Shut up dev_dbg_reatelimited() without DEBUG
>
> dev_dbg_reatelimited() without DEBUG printed "217078 callbacks
> suppressed". This shouldn't print anything without DEBUG.
>
> With CONFIG_DYNAMIC_DEBUG, the print should be configured as expected.
>
> Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
> Reported-by: Antti Palosaari <crope@iki.fi>
> ---
>   include/linux/device.h |   62 +++++++++++++++++++++++++++++------------------
>   1 files changed, 38 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 9648331..bb6ffcb 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -932,6 +932,32 @@ int _dev_info(const struct device *dev, const char *fmt, ...)
>
>   #endif
>
> +/*
> + * Stupid hackaround for existing uses of non-printk uses dev_info
> + *
> + * Note that the definition of dev_info below is actually _dev_info
> + * and a macro is used to avoid redefining dev_info
> + */
> +
> +#define dev_info(dev, fmt, arg...) _dev_info(dev, fmt, ##arg)
> +
> +#if defined(CONFIG_DYNAMIC_DEBUG)
> +#define dev_dbg(dev, format, ...)		     \
> +do {						     \
> +	dynamic_dev_dbg(dev, format, ##__VA_ARGS__); \
> +} while (0)
> +#elif defined(DEBUG)
> +#define dev_dbg(dev, format, arg...)		\
> +	dev_printk(KERN_DEBUG, dev, format, ##arg)
> +#else
> +#define dev_dbg(dev, format, arg...)				\
> +({								\
> +	if (0)							\
> +		dev_printk(KERN_DEBUG, dev, format, ##arg);	\
> +	0;							\
> +})
> +#endif
> +
>   #define dev_level_ratelimited(dev_level, dev, fmt, ...)			\
>   do {									\
>   	static DEFINE_RATELIMIT_STATE(_rs,				\
> @@ -955,33 +981,21 @@ do {									\
>   	dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
>   #define dev_info_ratelimited(dev, fmt, ...)				\
>   	dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || defined(DEBUG)
>   #define dev_dbg_ratelimited(dev, fmt, ...)				\
> -	dev_level_ratelimited(dev_dbg, dev, fmt, ##__VA_ARGS__)
> -
> -/*
> - * Stupid hackaround for existing uses of non-printk uses dev_info
> - *
> - * Note that the definition of dev_info below is actually _dev_info
> - * and a macro is used to avoid redefining dev_info
> - */
> -
> -#define dev_info(dev, fmt, arg...) _dev_info(dev, fmt, ##arg)
> -
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> -#define dev_dbg(dev, format, ...)		     \
> -do {						     \
> -	dynamic_dev_dbg(dev, format, ##__VA_ARGS__); \
> +do {									\
> +	static DEFINE_RATELIMIT_STATE(_rs,				\
> +				      DEFAULT_RATELIMIT_INTERVAL,	\
> +				      DEFAULT_RATELIMIT_BURST);		\
> +	DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);			\
> +	if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT) &&	\
> +	    __ratelimit(&_rs))						\
> +		__dynamic_pr_debug(&descriptor, pr_fmt(fmt),		\
> +				   ##__VA_ARGS__);			\
>   } while (0)
> -#elif defined(DEBUG)
> -#define dev_dbg(dev, format, arg...)		\
> -	dev_printk(KERN_DEBUG, dev, format, ##arg)
>   #else
> -#define dev_dbg(dev, format, arg...)				\
> -({								\
> -	if (0)							\
> -		dev_printk(KERN_DEBUG, dev, format, ##arg);	\
> -	0;							\
> -})
> +#define dev_dbg_ratelimited(dev, fmt, ...)			\
> +	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
>   #endif
>
>   #ifdef VERBOSE_DEBUG

That seems to work correctly now. I tested it using dynamic debugs. It 
was Hin-Tak who originally reported that bug for me after I added few 
ratelimited debugs for DVB stack. Thank you!

Reported-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Tested-by: Antti Palosaari <crope@iki.fi>


regards
Antti

-- 
http://palosaari.fi/