From f385f7d244134246f984975ed34cd75f77de479f Mon Sep 17 00:00:00 2001 From: Dai Ngo Date: Wed, 11 Jan 2023 12:17:09 -0800 Subject: NFSD: register/unregister of nfsd-client shrinker at nfsd startup/shutdown time Currently the nfsd-client shrinker is registered and unregistered at the time the nfsd module is loaded and unloaded. The problem with this is the shrinker is being registered before all of the relevant fields in nfsd_net are initialized when nfsd is started. This can lead to an oops when memory is low and the shrinker is called while nfsd is not running. This patch moves the register/unregister of nfsd-client shrinker from module load/unload time to nfsd startup/shutdown time. Fixes: 44df6f439a17 ("NFSD: add delegation reaper to react to low memory condition") Reported-by: Mike Galbraith Signed-off-by: Dai Ngo Signed-off-by: Chuck Lever --- fs/nfsd/nfs4state.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'fs/nfsd/nfs4state.c') diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 313f666d5357..db41358bd0d3 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4421,7 +4421,7 @@ nfsd4_state_shrinker_scan(struct shrinker *shrink, struct shrink_control *sc) return SHRINK_STOP; } -int +void nfsd4_init_leases_net(struct nfsd_net *nn) { struct sysinfo si; @@ -4443,16 +4443,6 @@ nfsd4_init_leases_net(struct nfsd_net *nn) nn->nfs4_max_clients = max_t(int, max_clients, NFS4_CLIENTS_PER_GB); atomic_set(&nn->nfsd_courtesy_clients, 0); - nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan; - nn->nfsd_client_shrinker.count_objects = nfsd4_state_shrinker_count; - nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS; - return register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client"); -} - -void -nfsd4_leases_net_shutdown(struct nfsd_net *nn) -{ - unregister_shrinker(&nn->nfsd_client_shrinker); } static void init_nfs4_replay(struct nfs4_replay *rp) @@ -8069,8 +8059,17 @@ static int nfs4_state_create_net(struct net *net) INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker); get_net(net); + nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan; + nn->nfsd_client_shrinker.count_objects = nfsd4_state_shrinker_count; + nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS; + + if (register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client")) + goto err_shrinker; return 0; +err_shrinker: + put_net(net); + kfree(nn->sessionid_hashtbl); err_sessionid: kfree(nn->unconf_id_hashtbl); err_unconf_id: @@ -8163,6 +8162,7 @@ nfs4_state_shutdown_net(struct net *net) struct list_head *pos, *next, reaplist; struct nfsd_net *nn = net_generic(net, nfsd_net_id); + unregister_shrinker(&nn->nfsd_client_shrinker); cancel_delayed_work_sync(&nn->laundromat_work); locks_end_grace(&nn->nfsd4_manager); -- cgit v1.2.3 From 7c24fa225081f31bc6da6a355c1ba801889ab29a Mon Sep 17 00:00:00 2001 From: Dai Ngo Date: Wed, 11 Jan 2023 16:06:51 -0800 Subject: NFSD: replace delayed_work with work_struct for nfsd_client_shrinker Since nfsd4_state_shrinker_count always calls mod_delayed_work with 0 delay, we can replace delayed_work with work_struct to save some space and overhead. Also add the call to cancel_work after unregister the shrinker in nfs4_state_shutdown_net. Signed-off-by: Dai Ngo Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever --- fs/nfsd/netns.h | 2 +- fs/nfsd/nfs4state.c | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'fs/nfsd/nfs4state.c') diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 8c854ba3285b..51a4b7885cae 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -195,7 +195,7 @@ struct nfsd_net { atomic_t nfsd_courtesy_clients; struct shrinker nfsd_client_shrinker; - struct delayed_work nfsd_shrinker_work; + struct work_struct nfsd_shrinker_work; }; /* Simple check to find out if a given net was properly initialized */ diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index db41358bd0d3..f194d029c3d6 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4411,7 +4411,7 @@ nfsd4_state_shrinker_count(struct shrinker *shrink, struct shrink_control *sc) if (!count) count = atomic_long_read(&num_delegations); if (count) - mod_delayed_work(laundry_wq, &nn->nfsd_shrinker_work, 0); + queue_work(laundry_wq, &nn->nfsd_shrinker_work); return (unsigned long)count; } @@ -6225,8 +6225,7 @@ deleg_reaper(struct nfsd_net *nn) static void nfsd4_state_shrinker_worker(struct work_struct *work) { - struct delayed_work *dwork = to_delayed_work(work); - struct nfsd_net *nn = container_of(dwork, struct nfsd_net, + struct nfsd_net *nn = container_of(work, struct nfsd_net, nfsd_shrinker_work); courtesy_client_reaper(nn); @@ -8056,7 +8055,7 @@ static int nfs4_state_create_net(struct net *net) INIT_LIST_HEAD(&nn->blocked_locks_lru); INIT_DELAYED_WORK(&nn->laundromat_work, laundromat_main); - INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker); + INIT_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker); get_net(net); nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan; @@ -8163,6 +8162,7 @@ nfs4_state_shutdown_net(struct net *net) struct nfsd_net *nn = net_generic(net, nfsd_net_id); unregister_shrinker(&nn->nfsd_client_shrinker); + cancel_work(&nn->nfsd_shrinker_work); cancel_delayed_work_sync(&nn->laundromat_work); locks_end_grace(&nn->nfsd4_manager); -- cgit v1.2.3