knfsd: Allow lockless lookups of the exports

Convert structs svc_expkey and svc_export to allow RCU protected lookups.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

2 files changed, 9 insertions, 7 deletions

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index a1143f7c2201..802993d8912f 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -46,7 +46,7 @@ static void expkey_put(struct kref *ref)
             !test_bit(CACHE_NEGATIVE, &key->h.flags))
                 path_put(&key->ek_path);
         auth_domain_put(key->ek_client);
-        kfree(key);
+        kfree_rcu(key, ek_rcu);
 }
 
 static void expkey_request(struct cache_detail *cd,
@@ -265,7 +265,7 @@ svc_expkey_lookup(struct cache_detail *cd, struct svc_expkey *item)
         struct cache_head *ch;
         int hash = svc_expkey_hash(item);
 
-        ch = sunrpc_cache_lookup(cd, &item->h, hash);
+        ch = sunrpc_cache_lookup_rcu(cd, &item->h, hash);
         if (ch)
                 return container_of(ch, struct svc_expkey, h);
         else
@@ -314,7 +314,7 @@ static void svc_export_put(struct kref *ref)
         auth_domain_put(exp->ex_client);
         nfsd4_fslocs_free(&exp->ex_fslocs);
         kfree(exp->ex_uuid);
-        kfree(exp);
+        kfree_rcu(exp, ex_rcu);
 }
 
 static void svc_export_request(struct cache_detail *cd,
@@ -780,7 +780,7 @@ svc_export_lookup(struct svc_export *exp)
         struct cache_head *ch;
         int hash = svc_export_hash(exp);
 
-        ch = sunrpc_cache_lookup(exp->cd, &exp->h, hash);
+        ch = sunrpc_cache_lookup_rcu(exp->cd, &exp->h, hash);
         if (ch)
                 return container_of(ch, struct svc_export, h);
         else
@@ -1216,9 +1216,9 @@ static int e_show(struct seq_file *m, void *p)
 }
 
 const struct seq_operations nfs_exports_op = {
-        .start  = cache_seq_start,
-        .next   = cache_seq_next,
-        .stop   = cache_seq_stop,
+        .start  = cache_seq_start_rcu,
+        .next   = cache_seq_next_rcu,
+        .stop   = cache_seq_stop_rcu,
         .show   = e_show,
 };
 
diff --git a/fs/nfsd/export.h b/fs/nfsd/export.h
index c8b74126ddaa..e7daa1f246f0 100644
--- a/fs/nfsd/export.h
+++ b/fs/nfsd/export.h
@@ -61,6 +61,7 @@ struct svc_export {
         u32                     ex_layout_types;
         struct nfsd4_deviceid_map *ex_devid_map;
         struct cache_detail     *cd;
+        struct rcu_head         ex_rcu;
 };
 
 /* an "export key" (expkey) maps a filehandlefragement to an
@@ -75,6 +76,7 @@ struct svc_expkey {
         u32                     ek_fsid[6];
 
         struct path             ek_path;
+        struct rcu_head         ek_rcu;
 };
 
 #define EX_ISSYNC(exp)          (!((exp)->ex_flags & NFSEXP_ASYNC))