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.
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
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