From: Wolfgang Walter Subject: Re: [patch] sunrpc: make closing of old temporary sockets work (was: problems with lockd in 2.6.22.6) Date: Wed, 12 Sep 2007 21:40:57 +0200 Message-ID: <200709122140.57783.wolfgang.walter@studentenwerk.mhn.de> References: <200709121407.11151.wolfgang.walter@studentenwerk.mhn.de> <18151.62510.891210.485277@notabene.brown> <20070912184222.GG4274@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Cc: Neil Brown , trond.myklebust@fys.uio.no, netdev@vger.kernel.org, nfs@lists.sourceforge.net, linux-kernel@vger.kernel.org To: "J. Bruce Fields" Return-path: In-Reply-To: <20070912184222.GG4274@fieldses.org> Sender: netdev-owner@vger.kernel.org List-ID: 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 = =2E21 > > and .22. > >=20 > > Bruce: for you :-) >=20 > OK, thanks! But, (as is alas often the case) I'm still confused: >=20 > > 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); >=20 > What is it that ensures svsk->sk_inuse isn't incremented or SK_BUSY s= et > after that test? Not all the code that does either of those is under > the same serv->sv_lock lock that this code is. >=20 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=20 enqueues it. If SK_BUSY is set its already enqueued and svc_sock_enqueu= e=20 ensures that it is not enqueued twice. Regards, --=20 Wolfgang Walter Studentenwerk M=FCnchen Anstalt des =F6ffentlichen Rechts