From 437f91451349a94d581cb9a928fa3958153f0b71 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 1 Oct 2018 10:41:50 -0400 Subject: [PATCH] NFS: Lockless DNS lookups Enable RCU protected lookup in the legacy DNS resolver. Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields --- fs/nfs/dns_resolve.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c index 060c658eab66..e93a5dc07c8c 100644 --- a/fs/nfs/dns_resolve.c +++ b/fs/nfs/dns_resolve.c @@ -65,6 +65,7 @@ struct nfs_dns_ent { struct sockaddr_storage addr; size_t addrlen; + struct rcu_head rcu_head; }; @@ -101,13 +102,21 @@ static void nfs_dns_ent_init(struct cache_head *cnew, } } +static void nfs_dns_ent_free_rcu(struct rcu_head *head) +{ + struct nfs_dns_ent *item; + + item = container_of(head, struct nfs_dns_ent, rcu_head); + kfree(item->hostname); + kfree(item); +} + static void nfs_dns_ent_put(struct kref *ref) { struct nfs_dns_ent *item; item = container_of(ref, struct nfs_dns_ent, h.ref); - kfree(item->hostname); - kfree(item); + call_rcu(item, nfs_dns_ent_free_rcu); } static struct cache_head *nfs_dns_ent_alloc(void) @@ -195,7 +204,7 @@ static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd, { struct cache_head *ch; - ch = sunrpc_cache_lookup(cd, + ch = sunrpc_cache_lookup_rcu(cd, &key->h, nfs_dns_hash(key)); if (!ch)