NFS: DNS resolver cache per network namespace context introduced

This patch implements DNS resolver cache creation and registration for each
alive network namespace context.
This was done by registering NFS per-net operations, responsible for DNS cache
allocation/register and unregister/destructioning instead of initialization and
destruction of static "nfs_dns_resolve" cache detail (this one was removed).
Pointer to network dns resolver cache is stored in new per-net "nfs_net"
structure.
This patch also changes nfs_dns_resolve_name() function prototype (and it's
calls) by adding network pointer parameter, which is used to get proper DNS
resolver cache pointer for do_cache_lookup_wait() call.

Note: empty nfs_dns_resolver_init() and nfs_dns_resolver_destroy() functions
will be used in next patch in the series.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/fs/nfs/dns_resolve.h b/fs/nfs/dns_resolve.h
index 199bb5543a91..2e4f596d2923 100644
--- a/fs/nfs/dns_resolve.h
+++ b/fs/nfs/dns_resolve.h
@@ -15,12 +15,22 @@ static inline int nfs_dns_resolver_init(void)
 
 static inline void nfs_dns_resolver_destroy(void)
 {}
+
+static inline int nfs_dns_resolver_cache_init(struct net *net)
+{
+        return 0;
+}
+
+static inline void nfs_dns_resolver_cache_destroy(struct net *net)
+{}
 #else
 extern int nfs_dns_resolver_init(void);
 extern void nfs_dns_resolver_destroy(void);
+extern int nfs_dns_resolver_cache_init(struct net *net);
+extern void nfs_dns_resolver_cache_destroy(struct net *net);
 #endif
 
-extern ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
-                struct sockaddr *sa, size_t salen);
+extern ssize_t nfs_dns_resolve_name(struct net *net, char *name,
+                size_t namelen, struct sockaddr *sa, size_t salen);
 
 #endif