On Mon, Feb 13, 2017 at 5:54 AM, Hans Liljestrand <ishkamiel@xxxxxxxxx> wrote: > On Sat, Feb 11, 2017 at 01:42:53AM -0500, David Windsor wrote: >> >> <snip> >> >>> Signed-off-by: David Windsor <dwindsor@xxxxxxxxx> >>> --- >>> 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); > > > Hi, > I'm not sure if I have this correctly; But both before and after the patch > free_session gets called when se_ref count was 1, shouldn't this have > changed with the +1 scheme? > > Also, since the !atomic_add_unless doesn't actually decrement when at 1, > doesn't this leave the se_ref as 1 when it's destroyed? The function seems > to always be locked, so perhaps this doesn't matter, but still seems a bit > risky. > Yes; I forgot the additional call to atomic_dec_and_test() before free_session(). Thanks! I'll resubmit this after seeing how the rest of this discussion goes. We may end up abandoning this refcounting case. > Thanks, > -hans > > >>> 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 >>> > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
