From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 3 Oct 2013 17:22:44 +0000 (-0400)
Subject: ncpfs: rcu-delay unload_nls() and freeing ncp_server
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1dcddd4abd2c6df7f28928ad5cafa4a1cd20030b;p=linux-beck.git

ncpfs: rcu-delay unload_nls() and freeing ncp_server

makes ->d_hash() and ->d_compare() safety in RCU mode independent
from vfsmount_lock.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index 4659da67e7f6..2cf2ebecb55f 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -782,6 +782,17 @@ out:
 	return error;
 }
 
+static void delayed_free(struct rcu_head *p)
+{
+	struct ncp_server *server = container_of(p, struct ncp_server, rcu);
+#ifdef CONFIG_NCPFS_NLS
+	/* unload the NLS charsets */
+	unload_nls(server->nls_vol);
+	unload_nls(server->nls_io);
+#endif /* CONFIG_NCPFS_NLS */
+	kfree(server);
+}
+
 static void ncp_put_super(struct super_block *sb)
 {
 	struct ncp_server *server = NCP_SBP(sb);
@@ -792,11 +803,6 @@ static void ncp_put_super(struct super_block *sb)
 
 	ncp_stop_tasks(server);
 
-#ifdef CONFIG_NCPFS_NLS
-	/* unload the NLS charsets */
-	unload_nls(server->nls_vol);
-	unload_nls(server->nls_io);
-#endif /* CONFIG_NCPFS_NLS */
 	mutex_destroy(&server->rcv.creq_mutex);
 	mutex_destroy(&server->root_setup_lock);
 	mutex_destroy(&server->mutex);
@@ -813,8 +819,7 @@ static void ncp_put_super(struct super_block *sb)
 	vfree(server->rxbuf);
 	vfree(server->txbuf);
 	vfree(server->packet);
-	sb->s_fs_info = NULL;
-	kfree(server);
+	call_rcu(&server->rcu, delayed_free);
 }
 
 static int ncp_statfs(struct dentry *dentry, struct kstatfs *buf)
diff --git a/fs/ncpfs/ncp_fs_sb.h b/fs/ncpfs/ncp_fs_sb.h
index c51b2c543539..b81e97adc5a9 100644
--- a/fs/ncpfs/ncp_fs_sb.h
+++ b/fs/ncpfs/ncp_fs_sb.h
@@ -38,7 +38,7 @@ struct ncp_mount_data_kernel {
 };
 
 struct ncp_server {
-
+	struct rcu_head rcu;
 	struct ncp_mount_data_kernel m;	/* Nearly all of the mount data is of
 					   interest for us later, so we store
 					   it completely. */