> On Jun 24, 2016, at 17:06, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>
> On Fri, Jun 24, 2016 at 10:55:47AM -0400, Trond Myklebust wrote:
>> Prevent callbacks from triggering while we're detaching the socket.
>
> What motivated this? Do we have a bug without it?
Code inspection. Without locking, what ensures that you don’t have another processor calling into, say, svc_tcp_state_change() while this processor is tearing down your svc_sock.
>
> --b.
>
>>
>> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>> ---
>> net/sunrpc/svcsock.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
>> index dadfec66dbd8..abe2da602fb8 100644
>> --- a/net/sunrpc/svcsock.c
>> +++ b/net/sunrpc/svcsock.c
>> @@ -1611,9 +1611,12 @@ static void svc_sock_detach(struct svc_xprt *xprt)
>> dprintk("svc: svc_sock_detach(%p)\n", svsk);
>>
>> /* put back the old socket callbacks */
>> + lock_sock(sk);
>> sk->sk_state_change = svsk->sk_ostate;
>> sk->sk_data_ready = svsk->sk_odata;
>> sk->sk_write_space = svsk->sk_owspace;
>> + sk->sk_user_data = NULL;
>> + release_sock(sk);
>>
>> wq = sk_sleep(sk);
>> if (sunrpc_waitqueue_active(wq))
>> --
>> 2.7.4
>
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