5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: NeilBrown neilb@suse.de
[ Upstream commit 1463b38e7cf34d4cc60f41daff459ad807b2e408 ]
We currently have a 'laundrette' for closing cached files - a different work-item for each network-namespace.
These 'laundrettes' (aka struct nfsd_fcache_disposal) are currently on a list, and are freed using rcu.
The list is not necessary as we have a per-namespace structure (struct nfsd_net) which can hold a link to the nfsd_fcache_disposal. The use of kfree_rcu is also unnecessary as the cache is cleaned of all files associated with a given namespace, and no new files can be added, before the nfsd_fcache_disposal is freed.
So add a '->fcache_disposal' link to nfsd_net, and discard the list management and rcu usage.
Signed-off-by: NeilBrown neilb@suse.de Signed-off-by: Chuck Lever chuck.lever@oracle.com --- fs/nfsd/filecache.c | 76 +++++++++------------------------------------ fs/nfsd/netns.h | 2 ++ 2 files changed, 17 insertions(+), 61 deletions(-)
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index fbc0628c599af..b99852b30308a 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -44,12 +44,9 @@ struct nfsd_fcache_bucket { static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
struct nfsd_fcache_disposal { - struct list_head list; struct work_struct work; - struct net *net; spinlock_t lock; struct list_head freeme; - struct rcu_head rcu; };
static struct workqueue_struct *nfsd_filecache_wq __read_mostly; @@ -62,8 +59,6 @@ static long nfsd_file_lru_flags; static struct fsnotify_group *nfsd_file_fsnotify_group; static atomic_long_t nfsd_filecache_count; static struct delayed_work nfsd_filecache_laundrette; -static DEFINE_SPINLOCK(laundrette_lock); -static LIST_HEAD(laundrettes);
static void nfsd_file_gc(void);
@@ -360,19 +355,13 @@ nfsd_file_list_remove_disposal(struct list_head *dst, static void nfsd_file_list_add_disposal(struct list_head *files, struct net *net) { - struct nfsd_fcache_disposal *l; + struct nfsd_net *nn = net_generic(net, nfsd_net_id); + struct nfsd_fcache_disposal *l = nn->fcache_disposal;
- rcu_read_lock(); - list_for_each_entry_rcu(l, &laundrettes, list) { - if (l->net == net) { - spin_lock(&l->lock); - list_splice_tail_init(files, &l->freeme); - spin_unlock(&l->lock); - queue_work(nfsd_filecache_wq, &l->work); - break; - } - } - rcu_read_unlock(); + spin_lock(&l->lock); + list_splice_tail_init(files, &l->freeme); + spin_unlock(&l->lock); + queue_work(nfsd_filecache_wq, &l->work); }
static void @@ -748,7 +737,7 @@ nfsd_file_cache_purge(struct net *net) }
static struct nfsd_fcache_disposal * -nfsd_alloc_fcache_disposal(struct net *net) +nfsd_alloc_fcache_disposal(void) { struct nfsd_fcache_disposal *l;
@@ -756,7 +745,6 @@ nfsd_alloc_fcache_disposal(struct net *net) if (!l) return NULL; INIT_WORK(&l->work, nfsd_file_delayed_close); - l->net = net; spin_lock_init(&l->lock); INIT_LIST_HEAD(&l->freeme); return l; @@ -765,61 +753,27 @@ nfsd_alloc_fcache_disposal(struct net *net) static void nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l) { - rcu_assign_pointer(l->net, NULL); cancel_work_sync(&l->work); nfsd_file_dispose_list(&l->freeme); - kfree_rcu(l, rcu); -} - -static void -nfsd_add_fcache_disposal(struct nfsd_fcache_disposal *l) -{ - spin_lock(&laundrette_lock); - list_add_tail_rcu(&l->list, &laundrettes); - spin_unlock(&laundrette_lock); -} - -static void -nfsd_del_fcache_disposal(struct nfsd_fcache_disposal *l) -{ - spin_lock(&laundrette_lock); - list_del_rcu(&l->list); - spin_unlock(&laundrette_lock); -} - -static int -nfsd_alloc_fcache_disposal_net(struct net *net) -{ - struct nfsd_fcache_disposal *l; - - l = nfsd_alloc_fcache_disposal(net); - if (!l) - return -ENOMEM; - nfsd_add_fcache_disposal(l); - return 0; + kfree(l); }
static void nfsd_free_fcache_disposal_net(struct net *net) { - struct nfsd_fcache_disposal *l; + struct nfsd_net *nn = net_generic(net, nfsd_net_id); + struct nfsd_fcache_disposal *l = nn->fcache_disposal;
- rcu_read_lock(); - list_for_each_entry_rcu(l, &laundrettes, list) { - if (l->net != net) - continue; - nfsd_del_fcache_disposal(l); - rcu_read_unlock(); - nfsd_free_fcache_disposal(l); - return; - } - rcu_read_unlock(); + nfsd_free_fcache_disposal(l); }
int nfsd_file_cache_start_net(struct net *net) { - return nfsd_alloc_fcache_disposal_net(net); + struct nfsd_net *nn = net_generic(net, nfsd_net_id); + + nn->fcache_disposal = nfsd_alloc_fcache_disposal(); + return nn->fcache_disposal ? 0 : -ENOMEM; }
void diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 021acdc0d03bb..9e8b77d2a3a47 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -185,6 +185,8 @@ struct nfsd_net {
/* utsname taken from the process that starts the server */ char nfsd_name[UNX_MAXNODENAME+1]; + + struct nfsd_fcache_disposal *fcache_disposal; };
/* Simple check to find out if a given net was properly initialized */