On Wed, Dec 19 2018, Dan Carpenter wrote:
> [ Ancient code. But NeilB changed get_cred() recently so Smatch thinks
> it understands it now. - dan ]
>
> Hello Jeff Layton,
>
> The patch d3d4152a5d59: "nfs: make sillyrename an async operation"
> from Sep 17, 2010, leads to the following static checker warning:
>
> fs/nfs/unlink.c:351 nfs_async_rename()
> warn: 'data->cred' isn't an ERR_PTR
It would have been impressive to determine that at the time, though I
think it was true.
At the time it was rpc_lookup_cred(), that provided data->cred.
That was
return rpcauth_lookupcred(&generic_auth, 0);
of which the key line is :
ret = auth->au_ops->lookup_cred(auth, &acred, flags);
and generic_auth.au_ops->lookup_cred was
return rpcauth_lookup_credcache(&generic_auth, acred, flags);
which can only return an error if
cred->cr_ops->cr_init != NULL &&
and
int res = cred->cr_ops->cr_init(auth, cred);
if (res < 0) {
There is no generic_auth.au_ops->cr_init, so no error can be return.
It is much easier to determine that now.
Thanks,
NeilBrown
From: NeilBrown <neilb@xxxxxxxx>
Date: Thu, 20 Dec 2018 10:29:55 +1100
Subject: [PATCH] NFS: remove unnecessary test for IS_ERR(cred)
As gte_current_cred() cannot return an error,
this test is not necessary.
It hasn't been necessary for years, but it wasn't so obvious
before.
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
fs/nfs/unlink.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index a227ab7d6891..79b97b3c4427 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -348,11 +348,6 @@ nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
task_setup_data.callback_data = data;
data->cred = get_current_cred();
- if (IS_ERR(data->cred)) {
- struct rpc_task *task = ERR_CAST(data->cred);
- kfree(data);
- return task;
- }
msg.rpc_argp = &data->args;
msg.rpc_resp = &data->res;
--
2.14.0.rc0.dirty
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