On Sat, 2017-02-11 at 01:42 -0500, David Windsor wrote: > <snip> > > > Signed-off-by: David Windsor <dwind...@gmail.com> > > --- > > fs/nfsd/nfs4state.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > > index a0dee8a..b0f3010 100644 > > --- a/fs/nfsd/nfs4state.c > > +++ b/fs/nfsd/nfs4state.c > > @@ -196,7 +196,7 @@ static void nfsd4_put_session_locked(struct > > nfsd4_session *ses) > > > > lockdep_assert_held(&nn->client_lock); > > > > - if (atomic_dec_and_test(&ses->se_ref) && is_session_dead(ses)) > > + if (!atomic_add_unless(&ses->se_ref, -1, 1) && is_session_des(ses)) > > This should read: > if (!atomic_add_unless(&ses->se_ref, -1, 1) && is_session_dead(ses)) > > > free_session(ses); > > put_client_renew_locked(clp); > > } > > @@ -1645,7 +1645,7 @@ static void init_session(struct svc_rqst *rqstp, > > struct nfsd4_session *new, stru > > new->se_flags = cses->flags; > > new->se_cb_prog = cses->callback_prog; > > new->se_cb_sec = cses->cb_sec; > > - atomic_set(&new->se_ref, 0); > > + atomic_set(&new->se_ref, 1); > > idx = hash_sessionid(&new->se_sessionid); > > list_add(&new->se_hash, &nn->sessionid_hashtbl[idx]); > > spin_lock(&clp->cl_lock); > > @@ -1792,7 +1792,7 @@ free_client(struct nfs4_client *clp) > > ses = list_entry(clp->cl_sessions.next, struct > > nfsd4_session, > > se_perclnt); > > list_del(&ses->se_perclnt); > > - WARN_ON_ONCE(atomic_read(&ses->se_ref)); > > + WARN_ON_ONCE((atomic_read(&ses->se_ref) > 1)); > > free_session(ses); > > } > > rpc_destroy_wait_queue(&clp->cl_cb_waitq); > > -- > > 2.7.4 > >
The basic idea here is that nfsv4 sessions have a "resting state" of 0. We want to keep them around, but if they go "dead" then we we'll tear them down if they aren't actively in use at the time. So, we still free the thing when the refcount goes to zero, but we have an extra condition before we free it on the put -- that the session is also "dead" (meaning that the client asked us to destroy it). Your patch doesn't look like it'll break anything, but I personally find it harder to follow that way. The freeable reference state will be 1 instead of the normal 0. -- Jeff Layton <jlay...@poochiereds.net>
