SUNRPC: Allow the cache_detail to specify alternative upcall mechanisms

For events that are rare, such as referral DNS lookups, it makes limited
sense to have a daemon constantly listening for upcalls on a channel. An
alternative in those cases might simply be to run the app that fills the
cache using call_usermodehelper_exec() and friends.

The following patch allows the cache_detail to specify alternative upcall
mechanisms for these particular cases.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 5c865e2d299e..6caffa34ac01 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -171,6 +171,11 @@ static void ip_map_request(struct cache_detail *cd,
         (*bpp)[-1] = '\n';
 }
 
+static int ip_map_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+        return sunrpc_cache_pipe_upcall(cd, h, ip_map_request);
+}
+
 static struct ip_map *ip_map_lookup(char *class, struct in6_addr *addr);
 static int ip_map_update(struct ip_map *ipm, struct unix_domain *udom, time_t expiry);
 
@@ -289,7 +294,7 @@ struct cache_detail ip_map_cache = {
         .hash_table     = ip_table,
         .name           = "auth.unix.ip",
         .cache_put      = ip_map_put,
-        .cache_request  = ip_map_request,
+        .cache_upcall   = ip_map_upcall,
         .cache_parse    = ip_map_parse,
         .cache_show     = ip_map_show,
         .match          = ip_map_match,
@@ -523,6 +528,11 @@ static void unix_gid_request(struct cache_detail *cd,
         (*bpp)[-1] = '\n';
 }
 
+static int unix_gid_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+        return sunrpc_cache_pipe_upcall(cd, h, unix_gid_request);
+}
+
 static struct unix_gid *unix_gid_lookup(uid_t uid);
 extern struct cache_detail unix_gid_cache;
 
@@ -622,7 +632,7 @@ struct cache_detail unix_gid_cache = {
         .hash_table     = gid_table,
         .name           = "auth.unix.gid",
         .cache_put      = unix_gid_put,
-        .cache_request  = unix_gid_request,
+        .cache_upcall   = unix_gid_upcall,
         .cache_parse    = unix_gid_parse,
         .cache_show     = unix_gid_show,
         .match          = unix_gid_match,