Re: [patch] sunrpc: make closing of old temporary sockets work (was: problems with lockd in 2.6.22.6)

On Wednesday 12 September 2007, J. Bruce Fields wrote:
On Wed, Sep 12, 2007 at 04:14:06PM +0200, Neil Brown wrote:
So it is in 2.6.21 and later and should probably go to .stable for .21
and .22.

Bruce: for you :-)

OK, thanks! But, (as is alas often the case) I'm still confused:

if (!test_and_set_bit(SK_OLD, &svsk->sk_flags))
continue;
- if (atomic_read(&svsk->sk_inuse) || test_bit(SK_BUSY, &svsk->sk_flags))
+ if (atomic_read(&svsk->sk_inuse) > 1
+ || test_bit(SK_BUSY, &svsk->sk_flags))
continue;
atomic_inc(&svsk->sk_inuse);
list_move(le, &to_be_aged);

What is it that ensures svsk->sk_inuse isn't incremented or SK_BUSY set
after that test? Not all the code that does either of those is under
the same serv->sv_lock lock that this code is.


This should not matter - SK_CLOSED may be set at any time.

svc_age_temp_sockets only detaches the socket, sets SK_CLOSED and then
enqueues it. If SK_BUSY is set its already enqueued and svc_sock_enqueue
ensures that it is not enqueued twice.

Regards,
--
Wolfgang Walter
Studentenwerk München
Anstalt des öffentlichen Rechts
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