cifs: store pointer to master tlink in superblock (try #2)

This is the second version of this patch, the only difference between
it and the first one is that this explicitly makes cifs_sb_master_tlink
a static inline.

Instead of keeping a tag on the master tlink in the tree, just keep a
pointer to the master in the superblock. That eliminates the need for
using the radix tree to look up a tagged entry.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

2 files changed, 5 insertions, 17 deletions

diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index 525ba59a4105..79576dac336f 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -43,8 +43,8 @@
 
 struct cifs_sb_info {
         struct radix_tree_root tlink_tree;
-#define CIFS_TLINK_MASTER_TAG           0       /* is "master" (mount) tcon */
         spinlock_t tlink_tree_lock;
+        struct tcon_link *master_tlink;
         struct nls_table *local_nls;
         unsigned int rsize;
         unsigned int wsize;
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 9eb327defa1d..197ac579a70b 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2914,11 +2914,11 @@ remote_path_check:
 
         spin_lock(&cifs_sb->tlink_tree_lock);
         radix_tree_insert(&cifs_sb->tlink_tree, pSesInfo->linux_uid, tlink);
-        radix_tree_tag_set(&cifs_sb->tlink_tree, pSesInfo->linux_uid,
-                           CIFS_TLINK_MASTER_TAG);
         spin_unlock(&cifs_sb->tlink_tree_lock);
         radix_tree_preload_end();
 
+        cifs_sb->master_tlink = tlink;
+
         queue_delayed_work(system_nrt_wq, &cifs_sb->prune_tlinks,
                                 TLINK_IDLE_EXPIRE);
 
@@ -3271,22 +3271,10 @@ out:
         return tcon;
 }
 
-static struct tcon_link *
+static inline struct tcon_link *
 cifs_sb_master_tlink(struct cifs_sb_info *cifs_sb)
 {
-        struct tcon_link *tlink;
-        unsigned int ret;
-
-        spin_lock(&cifs_sb->tlink_tree_lock);
-        ret = radix_tree_gang_lookup_tag(&cifs_sb->tlink_tree, (void **)&tlink,
-                                        0, 1, CIFS_TLINK_MASTER_TAG);
-        spin_unlock(&cifs_sb->tlink_tree_lock);
-
-        /* the master tcon should always be present */
-        if (ret == 0)
-                BUG();
-
-        return tlink;
+        return cifs_sb->master_tlink;
 }
 
 struct cifsTconInfo *