svn commit: r186209 - head/sys/net

[Kip Macy]

Yes.

On Dec 17, 2008, at 6:49, Robert Watson <rwatson at FreeBSD.org> wrote:

>
> On Wed, 17 Dec 2008, Kip Macy wrote:
>
>> Author: kmacy
>> Date: Wed Dec 17 04:33:52 2008
>> New Revision: 186209
>> URL: http://svn.freebsd.org/changeset/base/186209
>>
>> Log:
>> avoid trying to acquire a shared lock while holding an exclusive lock
>> by making the ifnet lock acquisition exclusive
>
> This seems unfortunate as the ifindex arrays get dereferenced a  
> moderate amount; perhaps ifnet_byindex_locked() and  
> ifaddr_byindex_locked() should be added for those special-case  
> callers that are aware of ifnet locking?
>
> Robert N M Watson
> Computer Laboratory
> University of Cambridge
>
>>
>> Modified:
>> head/sys/net/if.c
>>
>> Modified: head/sys/net/if.c
>> === 
>> === 
>> === 
>> =====================================================================
>> --- head/sys/net/if.c    Wed Dec 17 04:15:38 2008    (r186208)
>> +++ head/sys/net/if.c    Wed Dec 17 04:33:52 2008    (r186209)
>> @@ -197,9 +197,9 @@ ifnet_byindex(u_short idx)
>>    INIT_VNET_NET(curvnet);
>>    struct ifnet *ifp;
>>
>> -    IFNET_RLOCK();
>> +    IFNET_WLOCK();
>>    ifp = V_ifindex_table[idx].ife_ifnet;
>> -    IFNET_RUNLOCK();
>> +    IFNET_WUNLOCK();
>>    return (ifp);
>> }
>>
>> @@ -218,9 +218,9 @@ ifaddr_byindex(u_short idx)
>> {
>>    struct ifaddr *ifa;
>>
>> -    IFNET_RLOCK();
>> +    IFNET_WLOCK();
>>    ifa = ifnet_byindex(idx)->if_addr;
>> -    IFNET_RUNLOCK();
>> +    IFNET_WUNLOCK();
>>    return (ifa);
>> }
>>
>>