nfs: nfs_do_{ref,sub}mount() superblock argument is redundant

It's always equal to dentry->d_sb
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/nfs/internal.h

@@ -163,10 +163,10 @@ static inline void nfs_fs_proc_exit(void)
 
 /* nfs4namespace.c */
 #ifdef CONFIG_NFS_V4
-extern struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry);
+extern struct vfsmount *nfs_do_refmount(struct dentry *dentry);
 #else
 static inline
-struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry)
+struct vfsmount *nfs_do_refmount(struct dentry *dentry)
 {
 	return ERR_PTR(-ENOENT);
 }

fs/nfs/namespace.c

@@ -25,8 +25,7 @@ static LIST_HEAD(nfs_automount_list);
 static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
 int nfs_mountpoint_expiry_timeout = 500 * HZ;
 
-static struct vfsmount *nfs_do_submount(struct super_block *sb,
-					struct dentry *dentry,
+static struct vfsmount *nfs_do_submount(struct dentry *dentry,
 					struct nfs_fh *fh,
 					struct nfs_fattr *fattr);
 
@@ -164,9 +163,9 @@ struct vfsmount *nfs_d_automount(struct path *path)
 	}
 
 	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
-		mnt = nfs_do_refmount(path->mnt->mnt_sb, path->dentry);
+		mnt = nfs_do_refmount(path->dentry);
 	else
-		mnt = nfs_do_submount(path->mnt->mnt_sb, path->dentry, fh, fattr);
+		mnt = nfs_do_submount(path->dentry, fh, fattr);
 	if (IS_ERR(mnt))
 		goto out;
 
@@ -230,19 +229,17 @@ static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
 
 /**
  * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
- * @sb - superblock of parent directory
  * @dentry - parent directory
  * @fh - filehandle for new root dentry
  * @fattr - attributes for new root inode
  *
  */
-static struct vfsmount *nfs_do_submount(struct super_block *sb,
-					struct dentry *dentry,
+static struct vfsmount *nfs_do_submount(struct dentry *dentry,
 					struct nfs_fh *fh,
 					struct nfs_fattr *fattr)
 {
 	struct nfs_clone_mount mountdata = {
-		.sb = sb,
+		.sb = dentry->d_sb,
 		.dentry = dentry,
 		.fh = fh,
 		.fattr = fattr,
@@ -262,7 +259,7 @@ static struct vfsmount *nfs_do_submount(struct super_block *sb,
 	mnt = (struct vfsmount *)devname;
 	if (IS_ERR(devname))
 		goto free_page;
-	mnt = nfs_do_clone_mount(NFS_SB(sb), devname, &mountdata);
+	mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
 free_page:
 	free_page((unsigned long)page);
 out:

fs/nfs/nfs4namespace.c

@@ -161,20 +161,18 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
 
 /**
  * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
- * @sb - superblock of parent directory
  * @dentry - parent directory
  * @locations - array of NFSv4 server location information
  *
  */
-static struct vfsmount *nfs_follow_referral(struct super_block *sb,
-					    struct dentry *dentry,
+static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
 					    const struct nfs4_fs_locations *locations)
 {
 	struct vfsmount *mnt = ERR_PTR(-ENOENT);
 	struct nfs_clone_mount mountdata = {
-		.sb = sb,
+		.sb = dentry->d_sb,
 		.dentry = dentry,
-		.authflavor = NFS_SB(sb)->client->cl_auth->au_flavor,
+		.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
 	};
 	char *page = NULL, *page2 = NULL;
 	int loc, error;
@@ -224,7 +222,7 @@ static struct vfsmount *nfs_follow_referral(struct super_block *sb,
  * @dentry - dentry of referral
  *
  */
-struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry)
+struct vfsmount *nfs_do_refmount(struct dentry *dentry)
 {
 	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
 	struct dentry *parent;
@@ -257,7 +255,7 @@ struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry)
 	    fs_locations->fs_path.ncomponents <= 0)
 		goto out_free;
 
-	mnt = nfs_follow_referral(sb, dentry, fs_locations);
+	mnt = nfs_follow_referral(dentry, fs_locations);
 out_free:
 	__free_page(page);
 	kfree(fs_locations);