1 files changed, 30 insertions, 41 deletions

diff --git a/fs/nfs/nfs4idmap.c b/fs/nfs/nfs4idmap.c
index f331866dd418..9e1c48c5c0b8 100644
--- a/fs/nfs/nfs4idmap.c
+++ b/fs/nfs/nfs4idmap.c
@@ -203,7 +203,7 @@ int nfs_idmap_init(void)
 	printk(KERN_NOTICE "NFS: Registering the %s key type\n",
 		key_type_id_resolver.name);
 
-	cred = prepare_kernel_cred(NULL);
+	cred = prepare_kernel_cred(&init_task);
 	if (!cred)
 		return -ENOMEM;
 
@@ -306,15 +306,12 @@ static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
 				 const char *type, void *data,
 				 size_t data_size, struct idmap *idmap)
 {
-	const struct cred *saved_cred;
 	struct key *rkey;
 	const struct user_key_payload *payload;
 	ssize_t ret;
 
-	saved_cred = override_creds(id_resolver_cache);
-	rkey = nfs_idmap_request_key(name, namelen, type, idmap);
-	revert_creds(saved_cred);
-
+	scoped_with_creds(id_resolver_cache)
+		rkey = nfs_idmap_request_key(name, namelen, type, idmap);
 	if (IS_ERR(rkey)) {
 		ret = PTR_ERR(rkey);
 		goto out;
@@ -424,26 +421,16 @@ static void nfs_idmap_pipe_destroy(struct dentry *dir,
 		struct rpc_pipe_dir_object *pdo)
 {
 	struct idmap *idmap = pdo->pdo_data;
-	struct rpc_pipe *pipe = idmap->idmap_pipe;
 
-	if (pipe->dentry) {
-		rpc_unlink(pipe->dentry);
-		pipe->dentry = NULL;
-	}
+	rpc_unlink(idmap->idmap_pipe);
 }
 
 static int nfs_idmap_pipe_create(struct dentry *dir,
 		struct rpc_pipe_dir_object *pdo)
 {
 	struct idmap *idmap = pdo->pdo_data;
-	struct rpc_pipe *pipe = idmap->idmap_pipe;
-	struct dentry *dentry;
 
-	dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
-	if (IS_ERR(dentry))
-		return PTR_ERR(dentry);
-	pipe->dentry = dentry;
-	return 0;
+	return rpc_mkpipe_dentry(dir, "idmap", idmap, idmap->idmap_pipe);
 }
 
 static const struct rpc_pipe_dir_object_ops nfs_idmap_pipe_dir_object_ops = {
@@ -561,22 +548,20 @@ nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
 	return true;
 }
 
-static void
-nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
+static void nfs_idmap_complete_pipe_upcall(struct idmap_legacy_upcalldata *data,
+					   int ret)
 {
-	struct key *authkey = idmap->idmap_upcall_data->authkey;
-
-	kfree(idmap->idmap_upcall_data);
-	idmap->idmap_upcall_data = NULL;
-	complete_request_key(authkey, ret);
-	key_put(authkey);
+	complete_request_key(data->authkey, ret);
+	key_put(data->authkey);
+	kfree(data);
 }
 
-static void
-nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
+static void nfs_idmap_abort_pipe_upcall(struct idmap *idmap,
+					struct idmap_legacy_upcalldata *data,
+					int ret)
 {
-	if (idmap->idmap_upcall_data != NULL)
-		nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
+	if (cmpxchg(&idmap->idmap_upcall_data, data, NULL) == data)
+		nfs_idmap_complete_pipe_upcall(data, ret);
 }
 
 static int nfs_idmap_legacy_upcall(struct key *authkey, void *aux)
@@ -585,7 +570,7 @@ static int nfs_idmap_legacy_upcall(struct key *authkey, void *aux)
 	struct request_key_auth *rka = get_request_key_auth(authkey);
 	struct rpc_pipe_msg *msg;
 	struct idmap_msg *im;
-	struct idmap *idmap = (struct idmap *)aux;
+	struct idmap *idmap = aux;
 	struct key *key = rka->target_key;
 	int ret = -ENOKEY;
 
@@ -613,7 +598,7 @@ static int nfs_idmap_legacy_upcall(struct key *authkey, void *aux)
 
 	ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
 	if (ret < 0)
-		nfs_idmap_abort_pipe_upcall(idmap, ret);
+		nfs_idmap_abort_pipe_upcall(idmap, data, ret);
 
 	return ret;
 out2:
@@ -669,6 +654,7 @@ idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 	struct request_key_auth *rka;
 	struct rpc_inode *rpci = RPC_I(file_inode(filp));
 	struct idmap *idmap = (struct idmap *)rpci->private;
+	struct idmap_legacy_upcalldata *data;
 	struct key *authkey;
 	struct idmap_msg im;
 	size_t namelen_in;
@@ -678,10 +664,11 @@ idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 	 * will have been woken up and someone else may now have used
 	 * idmap_key_cons - so after this point we may no longer touch it.
 	 */
-	if (idmap->idmap_upcall_data == NULL)
+	data = xchg(&idmap->idmap_upcall_data, NULL);
+	if (data == NULL)
 		goto out_noupcall;
 
-	authkey = idmap->idmap_upcall_data->authkey;
+	authkey = data->authkey;
 	rka = get_request_key_auth(authkey);
 
 	if (mlen != sizeof(im)) {
@@ -703,18 +690,17 @@ idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 	if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
 		ret = -EINVAL;
 		goto out;
-}
+	}
 
-	ret = nfs_idmap_read_and_verify_message(&im,
-			&idmap->idmap_upcall_data->idmap_msg,
-			rka->target_key, authkey);
+	ret = nfs_idmap_read_and_verify_message(&im, &data->idmap_msg,
+						rka->target_key, authkey);
 	if (ret >= 0) {
 		key_set_timeout(rka->target_key, nfs_idmap_cache_timeout);
 		ret = mlen;
 	}
 
 out:
-	nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
+	nfs_idmap_complete_pipe_upcall(data, ret);
 out_noupcall:
 	return ret;
 }
@@ -728,7 +714,7 @@ idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 	struct idmap *idmap = data->idmap;
 
 	if (msg->errno)
-		nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
+		nfs_idmap_abort_pipe_upcall(idmap, data, msg->errno);
 }
 
 static void
@@ -736,8 +722,11 @@ idmap_release_pipe(struct inode *inode)
 {
 	struct rpc_inode *rpci = RPC_I(inode);
 	struct idmap *idmap = (struct idmap *)rpci->private;
+	struct idmap_legacy_upcalldata *data;
 
-	nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
+	data = xchg(&idmap->idmap_upcall_data, NULL);
+	if (data)
+		nfs_idmap_complete_pipe_upcall(data, -EPIPE);
 }
 
 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)