Subject: Re: [PATCH 08/12] netlink: Export genl_lock() API for use by modules

From: James Chapman <[email-masked]>
Date: Thu, 18 Mar 2010 17:46:29 +0000

Stephen Hemminger wrote:
> On Thu, 18 Mar 2010 10:22:10 +0000
> James Chapman <[email-masked]> wrote:
> 
>> This lets kernel modules which use genl netlink APIs serialize netlink
>> processing.
>>
>> Signed-off-by: James Chapman <[email-masked]>
>> ---
>>  include/linux/genetlink.h |    8 ++++++++
>>  net/netlink/genetlink.c   |    6 ++++--
>>  2 files changed, 12 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/linux/genetlink.h b/include/linux/genetlink.h
>> index b834ef6..61549b2 100644
>> --- a/include/linux/genetlink.h
>> +++ b/include/linux/genetlink.h
>> @@ -80,4 +80,12 @@ enum {
>>  
>>  #define CTRL_ATTR_MCAST_GRP_MAX (__CTRL_ATTR_MCAST_GRP_MAX - 1)
>>  
>> +#ifdef __KERNEL__
>> +
>> +/* All generic netlink requests are serialized by a global lock.  */
>> +extern void genl_lock(void);
>> +extern void genl_unlock(void);
>> +
>> +#endif /* __KERNEL__ */
>> +
>>  #endif	/* __LINUX_GENERIC_NETLINK_H */
>> diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
>> index a4b6e14..a28fda7 100644
>> --- a/net/netlink/genetlink.c
>> +++ b/net/netlink/genetlink.c
>> @@ -20,15 +20,17 @@
>>  
>>  static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
>>  
>> -static inline void genl_lock(void)
>> +void genl_lock(void)
>>  {
>>  	mutex_lock(&genl_mutex);
>>  }
>> +EXPORT_SYMBOL(genl_lock);
>>  
>> -static inline void genl_unlock(void)
>> +void genl_unlock(void)
>>  {
>>  	mutex_unlock(&genl_mutex);
>>  }
>> +EXPORT_SYMBOL(genl_unlock);
> 
> EXPORT_SYMBOL_GPL() for this?

I chose EXPORT_SYMBOL because other exported symbols in that module
aren't GPL-only. I don't mind which is used. Any preference, Thomas?

-- 
James Chapman
Katalix Systems Ltd
http://www.katalix.com
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